High Quality Content by WIKIPEDIA articles! The Arena Football League (AFL) is the highest level of professional indoor American football in the United States. It is currently the second longest running professional football league in the United States, after the National Football League. It was founded in 1987 by Jim Foster. It is played indoors on a smaller field than American football, resulting in a faster-paced and higher-scoring game. The sport was invented in the early 1980s and patented by Foster, a former executive of the United States Football League and the National Football League.