Tunnell graduated from Anderson High School in Austin, Texas, and then attended Baylor University in Waco, Texas, where he was a star pitcher on the Bears team from 1979 to 1981.
Following his playing career, Tunnell coached in the minor leagues for several years, including a brief stint as interim pitching coach with the Cincinnati Reds in 2006.
In July 2012, he was named interim bullpen coach of the Milwaukee Brewers, a position he held until 2018, when his contract was not renewed by the Brewers front office.[1]
After spending the previous four years as the Reds' bullpen coach, Tunnell was fired following the 2022 season on October 6, 2022.[2]