1977 season At Purdue, Herrmann joined new head coach
Jim Young, hoping to earn playing time as a freshman. Herrmann battled for the starting quarterback position with senior Joe Metallic in the offseason. Metallic was named the day one starter, but Herrmann was still expected to play. In the first game of the season against
Michigan State, Herrmann took over for Metallic in the second quarter, completing 20 of 32 passes for 282 yards with two touchdowns and two interceptions. Herrmann was named the
UPI Midwest Back of the Week in his debut. Young named Herrmann as the starter for the following week against
Ohio University, the first freshman quarterback to start for Purdue since Bob DeMoss in 1945. Herrmann picked apart the Ohio defense, finishing the 44–7 win with 23 completions on 36 attempts for 339 yards and a touchdown. The next week, Herrmann faced his first major opponent as a starter in #11-ranked Notre Dame. Herrmann and Purdue led at halftime before Notre Dame backup quarterback
Joe Montana came in to lead a rally, winning 31–24. Herrmann finished the game with 351 passing yards and three touchdowns. Later in his freshman season, Herrmann led the Boilermakers to a 34–21 win over
Iowa. Herrmann threw five touchdown passes in the game, tying a Purdue school record, and completed 13 total passes for 257 yards. Wide receiver Reggie Arnold caught four of Herrmann's touchdowns, setting a school and
Big Ten Conference record. Despite Purdue finishing the
1977 season with a 5–6 record, Herrmann led the Big Ten in passing with an overall season stat line of 175 completions on 319 attempts for a 54.9% completion rate, 2,453 passing yards, and 18 passing touchdowns. He was named to the
1977 All-Big Ten Second Team and was fifth in
NCAA Division I in passing yards.
1978 season As a sophomore in 1978, Herrmann continued to show his capabilities as a passer. The Boilermakers started the season 3–1 before upsetting #16-ranked
Ohio State, 27–16. Herrmann completed 22 of 34 passes for 210 yards and a touchdown in the victory. Purdue earned a #19 ranking in the
AP poll following their upset victory, the team's first top-25 ranking of Herrmann's career. The next week, Purdue beat
Illinois, 13–0, and took the lead in the Big Ten standings. Herrmann had 116 passing yards and one touchdown against Illinois, and moved into third place in all-time passing at Purdue. Herrmann led the Boilermakers to victories over Iowa and
Northwestern, where he was pulled early due to large Purdue leads, before tying
Wisconsin 24–24. Herrmann threw for seven touchdowns in this three game stretch, including a 75-yard pass to
tight end Dave Young (a future teammate on the Baltimore/Indianapolis Colts). Herrmann led Purdue to a 9-2-1 record in 1978 and a final ranking of #13 in the AP poll. The Boilermakers earned a trip to the
1978 Peach Bowl, where Herrmann led Purdue to a 41–21 victory over
Georgia Tech. Herrmann threw for 166 yards and two touchdowns and was named the game's most valuable player. He ended the 1978 season with 1,904 passing yards and 14 touchdowns. Herrmann was knocked out of the next game against
UCLA, leading to the Boilermakers upset loss. He responded the next week against #5-ranked Notre Dame, leading Purdue to a 28–22 comeback victory. Purdue was down 20–7 in the third quarter before scoring three touchdowns in the third and fourth quarters. Herrmann had two touchdown passes, one to Dave Young and one to former Carmel High School teammate Bart Burrell. Herrmann and Purdue eked out a victory over
Oregon before suffering an upset loss to
Minnesota, 14–31. Herrmann had 40 pass attempts for 235 yards against Minnesota, but threw four interceptions. Herrmann bounced back the next week in a 28–14 win over Illinois, during which he surpassed
Mike Phipps to become Purdue's all-time leading passer with 5,452 yards. Two weeks later, Herrmann broke Michigan State's
Ed Smith's Big Ten all-time passing record against Northwestern in a 20–16 victory, standing at 5,786 career passing yards after the game. Herrmann and #14 Purdue then upset #10-ranked
Michigan, 24–21, in a defensive struggle. Herrmann had a one-yard touchdown run in the game. In the 1979
Old Oaken Bucket rivalry game against
Indiana, Herrmann led Purdue with a career-high 26 pass completions for 269 yards in the 37–21 victory. Herrmann was injured in the fourth quarter, and left the game on a stretcher due to a
concussion. Purdue earned a berth to the
1979 Bluebonnet Bowl against
Tennessee. The Boilermakers got out to a 21–0 lead before letting Tennessee come back, 22–21, late in the fourth quarter. Herrmann drove Purdue 80 yards in the last 90 seconds of the game, capped by a 17-yard touchdown pass to Dave Young that sealed the 28–22 victory. Herrmann threw for 303 yards and three touchdowns on the day, and was named the game's most valuable player. Purdue finished the year ranked #10 in the AP poll with a 10–2 record, and Herrmann had a Big Ten-leading 182 pass completions for 2,074 yards and 13 touchdowns. Herrmann was named to the
1979 All-Big Ten Second Team and also finished eighth in the 1979
Heisman Trophy voting. Herrmann returned the following week against Wisconsin, and despite throwing for 347 yards he did not find the endzone. Herrmann left the game late in the fourth quarter with a leg injury, but Purdue still won, 12–6, on four field goals. Herrmann and Purdue then lost for the second consecutive season to UCLA, but during the game Herrmann was 25 for 42 with 282 yards and one touchdown. His lone touchdown pass to Burrell broke the Big Ten record for all-time touchdown passes with 49. Herrmann followed up the loss with a commanding victory over
Miami (OH), where he threw for 291 yards and two touchdowns. Head coach Jim Young had planned to take Herrmann out of the game at half time due to poor play, but instead allowed him to stay in the game and call plays from the huddle as an "on-field offensive coordinator." The next week against Minnesota, Herrmann continued his on-field playcalling duties in a 21–7 victory. Herrmann threw for 191 yards and two touchdowns before leaving the game with an injury. Herrmann's next game as full-time play caller saw Purdue defeat Illinois, 45–20. Herrmann threw for 371 yards and four touchdowns, setting a Big Ten single-game passing yards record. He was pulled from the game due to the lead, which allowed Illinois' quarterback
Dave Wilson to overtake Herrmann's record with 451 passing yards. On October 25, 1980, Herrmann broke the NCAA career passing yards record in a win over Michigan State. Herrmann led Purdue to a 36–25 comeback victory, and finished the game with 340 passing yards and a career total of 8,087 yards. He became the first collegiate quarterback to throw for more than 8,000 career yards, with the previous record of 7,818 yards held by
Washington State's
Jack Thompson. Herrmann continued his record setting pace the next week with a 52–31 victory over Northwestern. Herrmann completed 17 of 21 passes for 210 yards and three touchdowns, setting the NCAA record for career completions with 651 total. Purdue faced Iowa on November 8, 1980, where Herrmann set even more school and Big Ten Conference records. Herrmann threw for 439 yards and three touchdowns in only three quarters of play, as Purdue won 58–13. Herrmann's season-worst performance came in the second to last regular season game against #11 Michigan, where he threw four interceptions in a 26–0 loss. Herrmann rebounded the next week in the 1980 Old Oaken Bucket game, where he threw for 323 yards and a touchdown. He broke the 9,000 career passing yards mark in this game, also becoming the first NCAA quarterback to do so. In the
1980 Liberty Bowl, Herrmann and Purdue beat
Missouri, 28–25. Herrmann set a then-Liberty Bowl record with 289 passing yards and four touchdowns. He earned his third straight bowl game most valuable player award, an NCAA first. Herrmann earned many postseason accolades, including a
unanimous All-American selection to the
1980 All-America First Team,
1980 All-Big Ten First Team, the
Sammy Baugh Trophy, the
Chicago Tribune Silver Football as the Big Ten Conference most valuable player, and finished fourth in the 1980 Heisman Trophy voting. Herrmann was elected to the
College Football Hall of Fame in May 2010. ==Professional career==