Krenzel attended Henry Ford II High School (Sterling Heights, Mich.), and was an excellent student and a letterman in football (3 yrs), basketball (2 yrs), and baseball (1 yr). In football, as a senior, Krenzel completed 60 percent of his passes and threw for 1,760 yards and 25 touchdowns, and won USA Today honorable mention All-America accolades that year.
Krenzel played in college for The Ohio State Buckeyes. After quarterback Steve Bellisari was suspended from play due to an alcohol-related police charge late in the 2001 season, Krenzel earned the starting position against Michigan and led the Buckeyes to their first win in Ann Arbor since 1987. His most successful year was 2002, when he led Ohio State to the national championship. Krenzel's overall record with Ohio State is 24-3 as a starter.
Krenzel was drafted in the 2004 NFL Draft by the Chicago Bears, for whom he played the 2004 season. Despite poor passing statistics, Krenzel won his first three starts at quarterback with the Bears, including a win over the San Francisco 49ers, which was at the time starting Ken Dorsey at quarterback, the same quarterback that started for the Miami Hurricanes during the 2003 National Championship game. However, he lost his final two starts with the Bears and injured his ankle, ending his season. In 2005, he was cut by the Bears in the offseason and he signed with the Cincinnati Bengals. He was the third string quarterback on the team behind Carson Palmer and Jon Kitna. He was released in May 2006 due to an elbow injury that he sustained that eventually required Tommy John surgery. He has yet to play again in the NFL, though he has stated that he hopes for one more shot at football. He also shares the distinction of being a two-time Fiesta Bowl MVP with fellow Ohio State Buckeye A. J. Hawk.
He is also a spokesman for JD Equipment and has acted in several commercial spots.
Krenzel now is a partner of the Arthur Krenzel Lett Insurance Group in Columbus, Ohio and Winfield, West Virginia. Craig Lett, his partner, is the son of the Major League pitcher Jim Lett of the Cincinnati Reds.