A quality infielder and catcher, Jett spent 25 years in the Eastern Missouri Baseball Association from 1974-98. As a player he was on nine league championship teams and played in 12 EMBA all-star games. He helped the O’Fallon Colts win the league championship in 1974 and 1975. Kevin also was on the Roy Cox Reality team that won the league championship in 1979, part of a eight-year tenure with Cox. In addition, he was a player/manager for the Mavericks from 1997 to 1990 and led them to the league championship and Little League World Series in 1987. Jett also played for Cottleville & Harvester in 1994 and 1995, winning the league championship both years and the Little League World Series in 1994. Kevin also toiled for St. Peters from 1996-98 and won the league title in 1997 and 1998.

He also served as manager and for 10 years, he was president of the association. Kevin managed the St. Charles Post 312 American Legion team from 1998 to 2007, winning seven division championships and four district titles. He was also the president of the American Legion District 9 baseball program from 2001-2010. Since 2007, he has been an administrator for Post 312 in St. Charles.

Jett played three seasons for St. Charles High School and was captain his senior season in 1974. In 2012, Jeff was inducted into the St. Charles County Amateur Sports Hall of Fame.