A left-handed batter, Kubek signed his first professional contract with the Yankees and rose rapidly through the team’s farm system. He was 21 years old when he played his first game in Major League Baseball in 1957, and—except for one year (1962) spent largely in the U.S. military—remained with the Yankees until his retirement due to a back injury at the close of the 1965 season. In his prime he formed a top double play combination with second baseman (and roommate) Bobby Richardson on an infield that also featured third baseman Clete Boyer.

In 1957, teammate Sal Maglie praised Kubek when talking to Robert Creamer of Sports Illustrated. “He’s a nice boy, that Kubek. He’s going to be a great player. He’s a fine hitter right now. He hits with the pitch and it’s hard to fool him. His wrists are so quick he can wait to see where the pitch is thrown before he commits himself, and then he can push it to left or pull it to right. And he’s never satisfied with himself. That’s the sign of a good ballplayer.”

In 1957, Kubek won the American League Rookie of the Year Award. In Game 3 of the 1957 World Series, he had one of the best World Series games a rookie has ever had, going 3 for 5 with two home runs, three runs scored, and four RBI. Kubek is one of five rookies to hit two home runs in a World Series game. Another Yankee, Charlie Keller, had performed the feat in the 1939 World Series against the Cincinnati Reds and St. Louis Cardinal Willie McGee homered twice in the 1982 World Series against the Milwaukee Brewers. All three of these feats occurred in a Game 3; Kubek’s and McGee’s both occurred at Milwaukee County Stadium. The Atlanta Braves’ Andruw Jones homered twice in Game 1 of the 1996 World Series at Yankee Stadium. Michael Conforto of the New York Mets became the fifth member of this club when he hit two in Game 4 of the 2015 World Series on October 31, 2015.

Kubek played 1,092 games, 882 of them at shortstop (although he also was an outfielder and utility infielder in his early career), compiling a lifetime batting average of .266 with 57 home runs. The 38 doubles he totaled in 1961 remained the Yankee club record for shortstops until 2004, and his career fielding percentage and range factor were both above league average. During his nine years with the Yankees, he played on seven American League pennant winners (1957–58, 1960–64) and three world champions (1958, 1961–1962).

Upon his retirement, Kubek became a color analyst on NBC’s Saturday Game of the Week telecasts, teaming with play-by-play announcer Jim Simpson on the network’s backup games from 1966–68 and then joining Curt Gowdy to form the lead crew in 1969. He spent 24 years at NBC, teaming with such announcers as Simpson, Gowdy (whom Kubek later called his favorite partner), Joe Garagiola, and Bob Costas. Kubek could be considered baseball’s first network baseball analyst as contrasted with a color commentator, similar to Tim McCarver and Jim Kaat later.

On April 8, 1974, when Hank Aaron hit his record-breaking 715th career home run, Kubek, who was calling the game with Curt Gowdy and Joe Garagiola, criticized Bowie Kuhn on air for failing to be in attendance at Atlanta on that historic night. Kuhn later argued he had a prior engagement he could not break.

In a 1976 Esquire magazine article, sportswriter Harry Stein published an “All Time All-Star Argument Starter”, consisting of five ethnic baseball teams. Kubek was the shortstop on Stein’s Polish team. In 1982, Kubek was inducted into the National Polish-American Sports Hall of Fame.

Kubek is a Democrat. In 1976, he declined to go to South Carolina to campaign for former teammate Bobby Richardson, a Republican, who lost a close race for the U.S. House of Representatives to incumbent Democrat Kenneth Holland by a 51% to 48% margin.

In 1978, Kubek had said of New York Yankees’ owner George Steinbrenner that “He’s got an expensive toy. Baseball’s tough enough without an owner harassing you.” In a Sports Illustrated article published May 27, 1991, on the Yankees’ bad season, he would go on to criticize Steinbrenner once again by saying, “George’s legacy is not the World Series winners of ’77 and ’78 or having the best record of any team in the ’80s, his legacy is these past five seasons—teams with worse and worse records culminating in last year’s last-place finish.” Kubek also added, “George talked a lot about tradition, but it was all phony, it was just him trying to be part of the tradition. You can’t manufacture tradition in a plastic way. You have to have a certain class to go with it.”

The team of Kubek and Bob Costas (backing up Vin Scully and Joe Garagiola and later, Tom Seaver) proved to be a formidable pair. Costas was praised by fans for both his reverence and irreverence while Kubek was praised for his technical approach and historical perspective. One of the pair’s most memorable broadcasts was the “(Ryne) Sandberg Game” (between the Chicago Cubs and St. Louis Cardinals at Chicago’s Wrigley Field) on June 23, 1984. In the ninth inning, the Cubs, trailing 9–8, faced the premier relief pitcher of the time, Bruce Sutter. Sandberg, then not known for his power, slugged a home run to left field against the Cardinals’ ace closer. Despite this dramatic act, the Cardinals scored two runs in the top of the tenth. Sandberg came up again in the tenth inning, facing a determined Sutter with one man on base. Sandberg then shocked the national audience by hitting a second home run, even farther into the left field bleachers, to tie the game again. The Cubs went on to win in the 11th inning. When Sandberg hit that second home run, Costas said, “Do you believe it?!” The Cardinals’ Willie McGee also hit for the cycle in the same game.

In 1986, Kubek was on hand for the only Old-Timers’ Day at Yankee Stadium that he would take part in. That year, the event was a reunion of the 1961 Yankees and marked the recent passing of Roger Maris.

Kubek and Costas, who had worked together since 1983 (calling four American League Championship Series: 1983, 1985, 1987, and 1989), called the final edition (the 981st overall) of NBC’s Game of the Week which aired on September 30, 1989. That game featured the Toronto Blue Jays (Kubek was broadcaster, from 1977 to 1989 for the Blue Jays) beating the Baltimore Orioles 4–3 to clinch the AL East title at SkyDome.

Kubek added, “I want to go home and spend more time with my family. They deserve it more than anyone. I don’t need that ego stuff. I feel sorry for those who do.” Kubek’s resignation coincided with the bitter strike that wound up cancelling the World Series in 1994. In a 2008 New York Times article, Kubek claimed not to have seen a major league game since his retirement from broadcasting.

On December 22, 2008, Tony Kubek was named the recipient of the 2009 Ford C. Frick Award, an honor bestowed on broadcasters by the Baseball Hall of Fame.

Kubek lives in Appleton, Wisconsin, and is a supporter of the Fox Valley Lutheran High School and its baseball team. The National Polish-American Sports Hall of Fame on June 20, 2019 named its inaugural Excellence in Media Award the Tony Kubek Award and Adrian Wojnarowski of ESPN was honored.