The Boston Spirit are a team from The League's early history. They were one of the four founding teams of The League in 1916, and returned again in 1923. While the Spirit struggled throughout the 1930's, following the merger of Hugh Walker's and Marshall Cooper's leagues, they did manage to win the League Championship in 1939, defeating the Wichita franchise. The team came to an end in 1942, as they were eliminated from The League in an attempt to maximize coverage during World War II when The League lost many of its players to overseas service. It is believed that the Spirit was selected for contraction due to the ill feelings between Marshall Cooper and former Commissioner Hugh Walker, who had strong ties to the city of Boston.

Notable figures from the Boston Spirit include David Kent, the League Commissioner from 1958-1989. Kent was a former quarterback for the Spirit before being tapped to replace Guy Cooper as Commissioner following Cooper's indictment on gambling and racketeering charges. Kent was known for restoring The League's credibility and moral accountability following the gambling scandal associated with Guy Cooper, as well as maximizing The League's coverage by signing The League's first television contract. However, his legacy is somewhat clouded by the steroid scandal that broke upon his last year as commissioner, following the death of Las Vegas Aces player Deacon Taylor. Legendary running back Eric "The Red" Jorgenson also played his rookie year with the Spirit before the team folded, and he signed with the Chicago Scouts in the dispersal draft.