Born in Calgary, Alberta, Rypien moved to the United States in 1965 and was raised in Spokane, Washington. He was a star three-sport athlete at Shadle Park High School. As a senior in 1981, in one of the most controversial high school games in Washington state history, he led the Highlanders to the state title in basketball. All three of his varsity numbers (football, basketball, and baseball) were later retired by the school.

He accepted a football scholarship to Washington State University in Pullman, and joined the Delta Tau Delta fraternity. A knee injury in spring drills in 1982 redshirted him for that season and he nearly left football and WSU in November 1983. After a good showing as a late replacement to the roster in the Senior Bowl, he was selected by the Washington Redskins in the sixth round of the 1986 NFL Draft, the 146th overall pick and the eighth quarterback selected.

Rypien spent his first two years as a professional on the Redskins’ injured reserved list, first with a bad knee in 1986, then a bad back in 1987. He watched from the sidelines as the Redskins won Super Bowl XXII under coach Joe Gibbs in January 1988 behind the quarterbacking of veteran Doug Williams.

Rypien became the second stringer after Jay Schroeder, who had lost his job to Williams late in the 1987 season, was traded to the Los Angeles Raiders. In Week 4 against the newly relocated Phoenix Cardinals, Rypien got his first chance to start for an injured Williams and threw for 303 yards and two touchdowns in a 30-21 loss. In six starts, he went 3-3 and he appeared in nine games overall, including a four-touchdown game in a rematch against the Cardinals. He threw for 1,730 yards in those games and finished with three more touchdowns than Williams had, by a count of 18–15.

He has been a regular competitor at the American Century Championship, the annual competition at Lake Tahoe to determine the best golfers among American sports and entertainment celebrities. Rypien won the inaugural event in 1990, and won his second crown 24 years later in 2014; he has a total of 11 top ten finishes. Televised by NBC in July, the tournament is played at Edgewood Tahoe Golf Course in Stateline, Nevada.

1991 was Rypien’s best season; he threw for 3,564 yards and 28 touchdowns with 11 interceptions, leading the Redskins to Super Bowl XXVI after recording a 14-2 regular season record. He was named the MVP (Most Valuable Player) of the game, passing for 292 yards and 2 touchdowns and leading his team to a 37-24 win over the Buffalo Bills. Rypien, a native of Calgary, Alberta, Canada became the first foreign-born player to earn the honor. Rypien was named to the Pro Bowl in both 1989 and 1991.

Rypien was one of several players to benefit from the team’s success following their championship season. The Redskins signed him to a 3-year, $9 million deal entering the 1992 season. However, the team battled age and injuries and finished the regular season with a 9–7 record, barely making the playoffs. His passing yardage was a respectable 3,282 yards, but his passer rating fell from 97.9 in 1991 to 71.7 in 1992 and his interceptions outnumbered his touchdowns 17–13. Although a dominant team performance in the playoffs brought victory over the Minnesota Vikings in an NFC Wild Card away game, the Redskins eventually lost on a rainy, muddy field in a bruising game vs. the San Francisco 49ers, and the Rypien era was essentially over. Under new head coach Richie Petitbon, Rypien had his best training camp in 1993 and expectations were high following a Monday Night win over the defending Super Bowl Champion Dallas Cowboys. However, Rypien injured his knee in Week 2 against the Arizona Cardinals and the team began a precipitous slide toward a 4–12 season finish.

When he was healthy enough to return, Rypien performed spot duty, sharing time with the newly acquired Rich Gannon. The Redskins hired Norv Turner as their head coach in 1994. Rypien participated in offseason workouts, but the team released him from his contract. He went on to become a backup, serving with the Cleveland Browns in 1994, the St. Louis Rams in 1995 and 1997, and the Philadelphia Eagles in 1996. His last NFL touchdown pass came in relief of Eagles quarterback Ty Detmer, an 8-yarder to Irving Fryar with five seconds remaining in a 37-10 loss to the Indianapolis Colts. He signed with the Atlanta Falcons for the 1998 season but never made it to Atlanta. His son’s death from a malignant brain tumor that August caused Rypien to leave the game.

Rypien had a brief stint in NASCAR racing as a team owner, and was the original owner of the 2004 Nextel Cup championship-winning No. 97 team driven by Kurt Busch, having sold it to Jack Roush’s Roush Racing in 1997.

Rypien returned to football with the Colts in 2001. In August 2002, Rypien was signed by the Seattle Seahawks as a backup quarterback, played in two preseason games and finished 13-of-21 passing for 97 yards, but was cut early in September. His last professional game was on June 10, 2006; as part of a promotional gig, Rypien played one game for the Rochester Raiders of the Great Lakes Indoor Football League.

On June 8, 2006, Rypien was inducted into the National Polish-American Sports Hall of Fame.

In a 2018 interview with the Spokane Spokesman-Review, Rypien’s wife stated that she believes he is suffering from Chronic traumatic encephalopathy (CTE) from his years of playing football, with bizarre behavior occurring from time to time. Rypien himself confirmed that he has had struggles with mental health since his retirement from football, even attempting to take his own life by overdosing on pills before his wife stopped him. On June 30, 2019, he was arrested on suspicion of domestic violence and was charged with fourth-degree assault. This charge was dismissed on August 30, 2019.