John Thomas O'Sullivan is an American former professional football quarterback who played nine seasons in the National Football League (NFL), two seasons in NFL Europe and one season in the Canadian Football League (CFL). He played college football for the UC Davis Aggies, starting for three years and throwing for career totals of 10,745 yards and 96 touchdowns. He was named a first-team All-American in 2000 and a second-team All-American in 2001. He was inducted into the Cal Aggie Athletics Hall of Fame in 2008.

NFL Europe League was a professional American football league that functioned as the developmental minor league of the National Football League (NFL). Originally founded in 1989 as the World League of American Football, the league was envisioned as a transatlantic league encompassing teams from both North America and Europe. Initially, the WLAF consisted of seven teams in North America and three in Europe. It began play in 1991 and lasted for two seasons before suspending operations; while the league had been "wildly popular" in Europe, it failed to achieve success in North America. After a two-year hiatus, it returned as a six-team European league, with teams based in England, Germany, the Netherlands, Scotland, and Spain. NFL Europa was dissolved in 2007 due to its continued unprofitability and the NFL's decision to shift its focus towards hosting regular-season games in Europe; at the time of its closure, the league consisted of five German teams and one team based in the Netherlands.