Created in 1996 and based out of Mercer Island, Washington, the Blue Devils were an associate member playing for full membership in the North Division of the Pacific Football League for the 1997 season.  Mercer Island would be rebranded the Seattle Blue Devils along the way, with their Bellingham rivals continuing to bill them as the "Mercer Island" team in 1997 while southern league teams referred to them as "Seattle".  The Devils would win their first two games of '97 before a 7-game skid was finally halted with a 9-6 victory over Bellingham.

1998 began back-to-back two-win seasons for the Blue Devils as they struggled to generate offensive punch.

Following the 1998 season, Defensive Coordinator Jeff Scott wanted to buy the franchise, however negotiations broke down and Scott left to form the King County Jaguars for the 1999 season, taking with him part of the core of the Blue Devils defense.
 
Following the end of the 1999 season when the Blue Devils ceased operations, many of the players made their way to the Jaguars or the Puget Sound Jets which had became the regional "super team" of the 2000s.