Hartlieb emerged as the Hawkeyes' starting quarterback in 1987, winning the job from Dan McGwire. He passed for 3,092 yards and 19 touchdowns en route to a 9–3 record and a 20–19 victory over Wyoming in the 1987 Holiday Bowl. His seven passing touchdowns against Northwestern remain a school record.[2]
In 1988, Hartlieb set school records for passes attempted (460), completions (288), and yards gained (3,738).[3] Perhaps his greatest performance came on October 29, 1988, against Indiana. Hartlieb completed 44 of 60 pass attempts for 558 yards in a losing effort.[4] The Hawkeyes finished with a record of 6–4–3 and lost to NC State in the 1988 Peach Bowl.