For football, Jackson was recruited by Alabama, Georgia, and Oklahoma, all of whom were willing to break the color barrier just for Jackson. (Oklahoma had black football players before 1964, including Prentice Gautt, a star running back recruited in 1957, who played in the NFL.) Jackson declined Alabama and Georgia because he was fearful of the South at the time, and declined Oklahoma because they told him to stop dating white girls. For baseball, Jackson was scouted by Hans Lobert of the San Francisco Giants who was desperate to sign him. The Los Angeles Dodgers and Minnesota Twins also made offers, and the hometown Philadelphia Phillies gave him a tryout but declined because of his “hitting skills”.

Jackson graduated from Cheltenham High School in 1964, where he excelled in football, basketball, baseball, and track and field. A tailback in football, he injured his knee in an early season game in his junior year in the fall of 1962. He was told by the doctors he was never to play football again, but Jackson returned for the final game of the season. In that game, Jackson fractured five cervical vertebrae, which caused him to spend six weeks in the hospital and another month in a neck cast. Doctors told Jackson that he might never walk again, let alone play football, but Jackson defied the odds again. On the baseball team, he batted .550 and threw several no-hitters. In the middle of his senior year, Jackson’s father was arrested for bootlegging and was sentenced to six months in jail.

In the beginning of his sophomore year in 1966, Jackson replaced Rick Monday (the first player ever selected in the Major League Baseball draft and a future teammate with the A’s) at center field. He broke the team record for most home runs in a single season, led the team in numerous other categories and was first team All-American. Many scouts were looking at him play, including Tom Greenwade of the New York Yankees (who discovered Mickey Mantle), and Danny Murtaugh of the Pittsburgh Pirates. In his final game at Arizona State, he showed his potential by being only a triple away from hitting for the cycle, making a sliding catch, and having an assist at home plate. Jackson was the first college player to hit a home run out of Phoenix Municipal Stadium.

In the 1966 Major League Baseball draft on June 7, Jackson was selected by the Kansas City Athletics. He was the second overall pick, behind 17-year-old catcher Steve Chilcott, who was taken by the New York Mets. According to Jackson, Winkles told him that the Mets did not select him because he had a white girlfriend. Winkles later denied the story, stating that he did not know the reason why Jackson was not drafted by the Mets. It was later confirmed by Joe McDonald that the Mets drafted Chilcott because of need, the person running the Mets at the time was George Weiss, so the true motive may never be known.

Jackson played for two Class A teams in 1966, with the Broncs for just 12 games, and then 56 games with Modesto in the California League, where he hit 21 homers. He began 1967 with the Birmingham A’s in the Double-A Southern League in Birmingham, Alabama, where Jackson got his first taste of racism, being one of only a few blacks on the team. He credits the team’s manager at the time, John McNamara, for helping him through that difficult season.

Jackson debuted in the major leagues with the A’s in 1967 in a Friday doubleheader in Kansas City on June 9, a shutout sweep of the Cleveland Indians by scores of 2–0 and 6–0 at Municipal Stadium. (Jackson had his first career hit in the nightcap, a lead-off triple in the fifth inning off of long reliever Orlando Peña.)

The Athletics moved west to Oakland prior to the 1968 season. Jackson hit 47 home runs in 1969, and was briefly ahead of the pace that Roger Maris set when he broke the single-season record for home runs with 61 in 1961, and that of Babe Ruth when he set the previous record of 60 in 1927. Jackson later said that the sportswriters were claiming he was “dating a lady named ‘Ruth Maris.'”

Slumping at the plate in May 1970, Athletics owner Charlie O. Finley threatened to send Jackson to the minors. Jackson hit 23 home runs while batting .237 for the 1970 season. The Athletics sent him to play in Puerto Rico, where he played for the Santurce team and hit 20 homers and knocked in 47 runs to lead the league in both departments. Jackson hit a memorable home run in the 1971 All-Star Game at Tiger Stadium in Detroit. Batting for the American League against Pittsburgh Pirates pitcher Dock Ellis, the ball he hit soared above the right-field stands, striking the transformer of a light standard on the right field roof. While with the Angels in 1984, he hit a home run over that roof.

In 1971, the Athletics won the American League’s West division, their first title of any kind since 1931, when they played in Philadelphia. They were swept in three games in the American League Championship Series by the Baltimore Orioles. The A’s won the division again in 1972; their series with the Tigers went the full five games, and Jackson scored the tying run in the clincher on a steal of home. In the process, however, he tore a hamstring and was unable to play in the World Series. The A’s still managed to defeat the Cincinnati Reds in seven games. It was the first championship won by a San Francisco Bay Area team in any major league sport.

During spring training in 1972, Jackson showed up with a mustache. Though his teammates wanted him to shave it off, Jackson refused. Finley liked the mustache so much that he offered each player $300 to grow one, and hosted a “Mustache Day” featuring the last MLB player to wear a mustache, Frenchy Bordagaray, as master of ceremonies.

Jackson helped the Athletics win the pennant again in 1973, and was named Most Valuable Player of the American League for the season. The A’s defeated the New York Mets in seven hard-fought games in the World Series. This time, Jackson was not only able to play, but his performance led to his being awarded the Series’ MVP award. In the third inning of that seventh game, which ended in a 5–2 score, the A’s jumped out to a 4–0 lead as both Bert Campaneris and Jackson hit two-run home runs off Jon Matlack—the only two home runs Oakland hit the entire Series. The A’s won the World Series again in 1974, defeating the Los Angeles Dodgers in five games.

Jackson played 21 seasons and reached the post-season in 11 of them, winning six pennants and five World Series. His accomplishments include winning both the regular-season and World Series MVP awards in 1973, hitting 563 career home runs (sixth all-time at the time of his retirement), maintaining a .490 career slugging percentage, being named to 14 All-Star teams, and the dubious distinction of being the all-time leader in strikeouts with 2,597 (he finished with 13 more career strikeouts than hits) and second on the all-time list for most Golden sombreros (at least four strikeouts in a game) with 23 – he led this statistic until 2014, when he was surpassed by Ryan Howard. Jackson was the first major leaguer to hit 100 home runs for three different clubs, having hit over 100 for the Athletics, Yankees, and Angels. He is the only player in the 500 home run club that never had consecutive 30 home run seasons in a career.

In February 1974, Jackson won an arbitration case for a $135,000 salary for the season, nearly doubling his previous year’s $70,000. On June 5, outfielder Billy North and Jackson engaged in a clubhouse fight at Detroit’s Tiger Stadium. Jackson injured his shoulder, and catcher Ray Fosse, attempting to separate the combatants, suffered a crushed disk in his neck, costing him three months on the disabled list. In October, the A’s went on to win a third consecutive World Series.

Paid $140,000 in 1975 and one of nine Oakland players refusing to sign 1976 contracts, Jackson sought a three-year $600,000 pact. With free agency imminent after the season and the expectations of higher salaries for which Athletics owner Finley was unwilling to pay, he was traded along with Ken Holtzman and minor-league right-handed pitcher Bill Van Bommel to the Baltimore Orioles for Don Baylor, Mike Torrez, and Paul Mitchell on April 2, 1976. Jackson had not signed a contract and threatened to sit out the season; he reported to the Orioles four weeks later, and made his first plate appearance on May 2. Baltimore and Oakland both finished second in their respective divisions in 1976; the Yankees and Royals advanced to the ALCS, the first without the A’s since 1970. During Jackson’s lone season in Baltimore he stole 28 bases, a career-best.

The Yankees won the pennant in 1976 but were swept in the World Series by the Reds. A month later on November 29, they signed Jackson to a five-year contract totaling $2.96 million ($13,300,000 in current dollar terms). The number 9 that he had worn in Oakland and Baltimore was already used by Yankees third baseman Graig Nettles; Jackson asked for number 42 in memory of Jackie Robinson, but that number was given to pitching coach Art Fowler before the start of the season. Noting that Hank Aaron, at the time the holder of the career record for the most home runs, had just retired, Jackson asked for and received number 44 as a tribute to Aaron. Jackson wore number 20 for one game during spring training as a tribute to the also recently retired Frank Robinson, then he switched to number 44.

The Yankees’ home opener of the 1978 season, on April 13 against the Chicago White Sox, featured a new product, the “Reggie!” bar. In 1976, while playing in Baltimore, Jackson had said, “If I played in New York, they’d name a candy bar after me.” The Standard Brands company responded with a circular “bar” of peanuts dipped in caramel and covered in chocolate, a confection that was originally named the “Wayne Bun” as it was made in Fort Wayne, Indiana. The “Reggie!” bars were handed to fans as they walked into Yankee Stadium. Jackson hit a home run, and when he returned to right field the next inning, fans began throwing the Reggie bars on the field in celebration. Jackson told the press that this confused him, thinking that maybe the fans did not like the candy. The Yankees won the game, 4–2.

Jackson’s first season with the Yankees in 1977 was a difficult one. Although team owner George Steinbrenner and several players, most notably catcher and team captain Thurman Munson and outfielder Lou Piniella, were excited about his arrival, the team’s field manager Billy Martin was not. Martin had managed the Tigers in 1972, when Jackson’s A’s beat them in the playoffs. Jackson was once quoted as saying of Martin, “I hate him, but if I played for him, I’d probably love him.”

Jackson has consistently denied saying anything negative about Munson in the interview and he has said that his quotes were taken out of context. However, Dave Anderson of The New York Times subsequently wrote that he had drinks with Jackson in July 1977, and that Jackson told him, “I’m still the straw that stirs the drink. Not Munson, not nobody else on this club.” Regardless, as Munson was beloved by his teammates, Martin, Steinbrenner and Yankee fans, the relationships between them and Jackson became very strained.

Jackson appeared in the film The Naked Gun: From the Files of Police Squad!, portraying an Angels outfielder hypnotically programmed to kill the Queen of the United Kingdom. He also appeared in Richie Rich, BASEketball, Summer of Sam and The Benchwarmers. In 1979, Jackson was a guest star in an episode of the television sitcom Diff’rent Strokes and also in an episode of The Love Boat. He played himself in the Archie Bunker’s Place episode “Reggie-3 Archie-0” in 1982, a 1990 MacGyver episode, “Squeeze Play”, The Jeffersons episode “The Unnatural” from 1985, and the Malcolm in the Middle episode “Polly in the Middle”, from 2004. Jackson was also considered for the role of Geordi La Forge in the series Star Trek: The Next Generation, a role that ultimately went to LeVar Burton. From 1981 to 1982 he hosted for Nickelodeon’s Reggie Jackson’s World of Sports.

In 1980, Jackson batted .300 for the only time in his career, and his 41 home runs tied with Ben Oglivie of the Milwaukee Brewers for the American League lead. However, the Yankees were swept in the ALCS by the Kansas City Royals. That year, he won the inaugural Silver Slugger Award as a designated hitter.

As he entered the last year of his Yankee contract in 1981, Jackson endured several difficulties from George Steinbrenner. After the owner consulted Jackson about signing then-free agent Dave Winfield, Jackson expected Steinbrenner to work out a new contract for him as well. Steinbrenner never did (some say never intending to) and Jackson played the season as a free agent. Jackson started slowly with the bat, and when the 1981 Major League Baseball strike began, Steinbrenner invoked a clause in Jackson’s contract forcing him to take a complete physical examination. Jackson was outraged and blasted Steinbrenner in the media. When the season resumed, Jackson’s hitting improved, partly to show Steinbrenner he wasn’t finished as a player. He hit a long home run into the upper deck in Game Five of the strike-forced 1981 American League Division Series with the Brewers, and the Yankees went on to win the pennant again. However, Jackson injured himself running the bases in Game Two of the 1981 ALCS and missed the first two games of the World Series, both of which the Yankees won.

On April 27, 1982, in Jackson’s first game back at Yankee Stadium with the Angels, he broke out of a terrible season-starting slump to hit a home run off former teammate Ron Guidry. The at-bat began with Yankee fans, angry at Steinbrenner for letting Jackson get away, starting the “Reg-GIE!” chant, and ended it with the fans chanting “Steinbrenner sucks!” By the time of Jackson’s election to the Hall of Fame, Steinbrenner had begun to say that letting him go was the biggest mistake he had made as Yankee owner.

That season, the Angels won the American League West, and would do so again in 1986, but lost the American League Championship Series both times. On September 17, 1984, on the 17th anniversary of the day he hit his first home run, he hit his 500th, at Anaheim Stadium off Bud Black of the Royals.

In 1987, he signed a one-year contract to return to the A’s, wearing the number 44 with which he was now most associated rather than the number 9 he previously wore in Oakland. He announced he would retire after the season, at the age of 41. In his last at-bat, at Comiskey Park in Chicago on October 4, he collected a broken-bat single up the middle, but the A’s lost to the White Sox, 5–2. Jackson was the last player in the major leagues to have played for the Kansas City Athletics.

Jackson has endured three fires to personal property, including a June 20, 1976 fire at his home in Oakland that destroyed his 1973 MVP award, World Series trophies and All-Star rings. The same home was again burned down during the Oakland firestorm of 1991, which destroyed more baseball memorabilia in addition to other valuable collections. In 1988, a warehouse holding several of Jackson’s collectible cars was damaged in a fire, with several of the cars, valued at $3.2 million, ruined.

Jackson was inducted to the Hall of Fame in 1993. He chose to wear a Yankees cap on his Hall of Fame plaque after the Oakland Athletics unceremoniously fired him from a coaching position in 1991.

The Yankees retired Jackson’s uniform number 44 on August 14, 1993, shortly after his induction into the Hall of Fame. The Athletics retired his number 9 on May 22, 2004. He is one of only ten MLB players to have their numbers retired by more than one team, and one of only four to have different numbers retired by two MLB teams.

In 1999, Jackson placed 48th on The Sporting News’ 100 Greatest Baseball Players list. That same year, he was named one of 100 finalists for the Major League Baseball All-Century Team, but was not one of the 30 players chosen by the fans.

The Yankees dedicated a plaque in Jackson’s honor on July 6, 2002 that now hangs in Monument Park at Yankee Stadium. The plaque calls him “One of the most colorful and exciting players of his era” and “a prolific hitter who thrived in pressure situations.” Each Yankee so honored and still living was on hand for the dedication: Phil Rizzuto, Yogi Berra, Whitey Ford and Don Mattingly. Ron Guidry, a teammate of Jackson’s for all five of his seasons with the Yankees, was there, and was to be honored with a Monument Park plaque the next season. Willie Mays, Hank Aaron and Ernie Banks, players whom Jackson admired while growing up, attended the ceremony at his invitation. Like Jackson, each was a member of the Hall of Fame and had hit over 500 career home runs. Each had also played in the Negro Leagues, as had Jackson’s father, Martinez Jackson.

In Tampa in 2005, Jackson’s car was struck from behind and flipped over several times. Jackson escaped with minor injuries, later saying “…it was God tapping me on the shoulder… It makes you think about your purpose, about His plan for you.”

In 2007, ESPN aired a miniseries called The Bronx Is Burning about the 1977 Yankees, with the conflicts and controversies involving Jackson, portrayed by Daniel Sunjata, a central part of the storyline. The series infuriated Jackson, as he felt that he was portrayed as selfish and arrogant. He also expressed frustration that the filmmakers did not consult with him while making the miniseries, saying “I feel betrayed.”

In 2008, Jackson threw the ceremonial first pitch at the Yankees’ opening-day game, the last at the original Yankee Stadium. He also threw out the first pitch at the first game at the new Yankee Stadium (an exhibition game).

On October 9, 2009, Jackson threw the ceremonial opening pitch at Game 2 of the ALDS between the Yankees and the Minnesota Twins. On October 18, 2010, the Ride of Fame honored Jackson with his image on a New York City double-decker tour bus.

He co-authored a book in 2010, Sixty-Feet Six-Inches, with fellow Hall of Famer Bob Gibson. The book, whose title refers to the distance between the pitcher’s mound and home plate, details their careers and approach to the game.

On September 5, 2018, before an Athletics game against the Yankees in Oakland, Jackson was inducted into the new Oakland Athletics Hall of Fame. He joined fellow inductees Rickey Henderson, Dave Stewart, Dennis Eckersley, Catfish Hunter and Rollie Fingers.