On March 31, 2012, the Rockford IceHogs of the American Hockey League (AHL) signed Simpson to an amateur try-out agreement,[1] allowing the goaltender to make his professional debut in the AHL before the end of the 2011–12 season. On May 29, 2012, Simpson was signed by the Chicago Blackhawks of the National Hockey League (NHL) to a three-year entry-level contract.[2]
On July 15, 2015, Simpson was signed to a one-year AHL contract with the Stockton Heat, continuing his stay in Stockton after the previous season with former ECHL club, the Stockton Thunder.[4] In the 2015–16 season, Simpson split the year between the Heat and ECHL affiliate, the Adirondack Flames. As the Heat's third choice goaltender, he recorded a 3-4 record in 11 appearances.
As a free agent in the off-season from the Heat, Simpson secured a one-year AHL contract with the San Antonio Rampage, an affiliate to the Colorado Avalanche, on July 18, 2016.[5] He began the 2016–17 season with secondary affiliate and former team, the Colorado Eagles of the ECHL. Throughout the year, Simpson was recalled to the Rampage on multiple occasions, recording just 1 win in 9 games. He was returned to the Eagles for the playoffs, and served as backup in winning two series clinching games as Colorado claimed the Kelly Cup.