Kruczek earned All-America in 1975 as a quarterback at Boston College where he set several B.C. passing and total offense records. He was selected in the second round of the 1976 NFL Draft by the Pittsburgh Steelers and played in 29 games for them from 1976–1979 and was a member of Super Bowl championship squads in 1978 and 1979.
Kruczek distinguished himself in the NFL as a rookie in 1976 when he stepped into the lineup for an injured Terry Bradshaw and led the Steelers to six consecutive victories en route to the AFC title game. This record for wins as rookie stood until 2004 when it was surpassed by another Steeler, Ben Roethlisberger. He concluded his NFL career in 1980 with the Washington Redskins.
Kruczek led the fledgling Division 1-A program to some of its biggest successes. In his first season, he led the Knights to a 9-2 record and had a verbal commitment to playing in the first Oahu Bowl. However, those plans were dashed when Miami upset undefeated UCLA, and the resulting domino effect left the Knights out of what would have been their first bowl game ever. Another highlight was an upset win over the 3-8 University of Alabama Crimson Tide in 2000, which gave UCF its first victory over a program from a Bowl Championship Series automatic qualifying conference.
Kruczek's UCF Knights squad joined the Mid-American Conference as a football-only member starting in the 2002 season, with many pundits expecting the team to win the MAC's Eastern Division championship. After a successful debut season in 2002 in which Kruczek's team finished 7-5 and earned second place in the MAC East, UCF struggled mightily in 2003, going 3-9. Starting quarterback Ryan Schneider was dismissed from the team for academic violations and UCF struggled to a 3-7 record before Kruczek was dismissed with two games remaining in the season. After a humiliating loss to MAC bottom dweller Eastern Michigan, Kruczek was fired despite having signed a three-year contract extension at the start of the season. Kruczek was replaced by George O'Leary for the 2004 season, and UCF went 0-11 that year with much of the blame falling on Kruczek's poor recruiting and lax disciplinary standards.