Kramer appeared in five games of his rookie season in 1977, with one start and four mop-up roles as the heir apparent to
Fran Tarkenton, although when Tarkenton was hurt late in the season,
Bob Lee would be the starter for four of the last five games. In the 12th game of the year, Minnesota trailed the
San Francisco 49ers 24–7 in the fourth quarter, and Kramer was brought in to replace Lee. He went 9-of-13 for 188 yards and three touchdowns to win 28–27, becoming the youngest Vikings quarterback to do so until the 2025 season (
J J. McCarthy). The following week, he made his first ever start against the
Oakland Raiders. He went 16-of-34 for 177 yards with a touchdown and three interceptions in the 35–13 loss. The following year, Kramer would end up in mop-up duty as Tarkenton started each game for his final season. For the 1979 season, Kramer would become fully installed as the starter. He earned the nickname "Two-Minute Tommy" for his reputation with comebacks, as he would lead the Vikings to nineteen comebacks (and one in the playoffs), with fifteen in the fourth quarter, with 1980 and 1985 having four from Kramer in each year. However, Kramer would be plagued by injuries in his eleven seasons spent with the Vikings, since he started 109 of a possible 152 games for the team over his tenure, and he started each game of a season just twice (1979 and 1982), beset by knee and shoulder injuries to go alongside concussions. Kramer had knee and shoulder injuries, multiple concussions and a 1987 preseason spine injury that he said “basically pretty much ended my career.”
The 1980 season proved a pivotal moment for him and the Vikings. Kramer would go 8–7 as a starter while leading the Vikings back to the postseason for the first time since 1978. He threw 3,397 yards with 23 touchdowns to 24 interceptions while having a 55.7 completion percentage. Kramer saved his best for near-last in the season. Facing the
Cleveland Browns in the penultimate game of the regular season, he would take part of an iconic moment for the Vikings, as he threw a game-winning
Hail Mary pass with six seconds left. They had trailed 23–9 in the fourth quarter, but Kramer threw three touchdowns in the quarter, including two to
Ahmad Rashad late. On the final play of the game, Rashad was clustered in a group of Browns defenders but managed to catch the ball and carry himself into the end zone. The play, known as
Miracle at the Met, clinched a division title for the Vikings. Kramer had his best game to that point, throwing 38-of-49 for 456 yards with four touchdowns. In the postseason that year, he faced off against the
Philadelphia Eagles. Although they led 14–7 at halftime, a series of turnovers led to a 31–16 loss, and Kramer threw 19-of-39 for 209 yards with one touchdown and five interceptions. In 1982, Kramer led the Vikings to the postseason with a strike-shortened 5–4 record. Facing the
Atlanta Falcons in Minnesota, the Falcons led in the fourth quarter 21–16 before Kramer led them to a comeback to pull off a 30–24 win. He threw 20-of-34 passes for 253 yards with two touchdowns and one interception to lead the Vikings to the second round of the playoffs. Facing the
Washington Redskins the following week, Kramer could not quite generate magic, as Washington won 21–7 on their way to the
Super Bowl. Kramer threw 18-of-39 for 252 yards. Kramer enjoyed his last flash of brilliance in 1986. He went 7–6 in his thirteen starts while throwing for 3,000 yards with 24 touchdowns to ten interceptions while leading the league in passer rating with 92.6. Kramer had his highlight day on September 28, 1986, as he torched the
Green Bay Packers, even though his overall record against the Packers was 6–9, for six touchdown passes (with four in the first quarter) on a 16-of-25 day for 241 yards. He was named to the Pro Bowl for the first and only time. It was the last season which featured Kramer as the primary starter for the Vikings (starting thirteen games). In 1987, Kramer would split time with
Wade Wilson (who had been on the team since 1981), with Kramer starting five games and Wilson starting seven, with Kramer noting a preseason injury to his spine as the injury that hastened his end of career. Kramer threw four touchdowns to three interceptions in his 81 passes for six game appearances. Kramer was the starting quarterback when the Vikings sneaked into the playoffs at 8–7, although he was taken out after a few drives for Wilson. Kramer (who was hurt on the first play of the game) was 5-of-9 on 50 yards as the Vikings rolled to a 44–10 win over the
New Orleans Saints with Wilson at the helm. From there, the Vikings went to the NFC Championship Game with Wilson starting the next two games. For 1988, he made six starts with appearances in four other games. While going 4–2, he threw for 1,264 yards with five touchdowns to nine interceptions on 173 total pass attempts. For 1989, he closed out his Vikings career with appearances in eight games and four starts while throwing 906 yards and seven touchdowns and interceptions. His final appearance in a Vikings uniform was mop-up duty late in a playoff loss to San Francisco. He went 9-of-19 for 110 yards and an interception in the 41–13 loss. He was released after the season. Kramer was signed by the
New Orleans Saints in 1990. He appeared in only one game for the Saints (against the Vikings) and retired after the 1990 season. ==NFL career statistics==