After winning the league championship in 1975, Foster worked with a well known European soccer coach and sports promoter Bob Kapp, to organize and introduce the sport of American (pro level) football to Europe for the first time, during a five-game exhibition tour in June 1977 between the Nite Hawks and the Chicago Lions of the Northern States AAA Pro Football League playing exhibition games in major European cities, including Paris, Lille, Frankfurt, Gratz and Vienna.
After the season ended, he then accepted an offer to move back to the Midwest to serve as executive vice president of the Chicago Blitz of the USFL.
When the fateful decision was later made to move the USFL in 1985 from a spring season to a fall season on a head-to-head basis with the NFL, Foster made a pivotal decision to begin working full-time on carefully testing and researching the mechanics and basic rules of the new game he had invented before actually launching the Arena Football League (AFL), starting play in early June 1987.
A very difficult decision was made to sell the team due to rapidly raising personnel operating expenses, as well as having to continue to play in an iconic, but antiqued and undersized venue in Des Moines.
In 1990, thanks to a lengthy, successful effort by well known Chicago-based intellectual properties attorney, William Niro, Foster was granted a US patent on the game of arena football and the equipment unique to it, particularly the end zone Goalside Rebound Nets and padded Sideline Barriers, meaning that other indoor football leagues not affiliated with the AFL were legally required to play by at least somewhat different rules than the ones the AFL uses until the patent expired in September 2007. as a result, Arena Football became the first USA based team sport to ever play with a US patent in place.
This primarily included no use of the Goalside/cross bar and flanking nets apparatus, as well as that no active usage of the Sideline Barriers could be incorporated into game playing rules.
Additional patents were also secured for the arena football game system on an international basis, primarily in multiple European countries and also Mexico.
His younger son Palmer, became a 3rd generation Iowa Hawkeye student-athlete, following in the footsteps of his grandfather Derrold (Pat) Foster (football, track and JV basketball and baseball 1945–1949), then by his father Jim.