The 46-year-old Doan spent his entire 21-year playing career with the Coyotes franchise, starting in its final year in Winnipeg in 1995-96. He was an All-Star in 2004 and 2009.
After his retirement as a player following the 2016-17 season, Doan spent three years in the NHL's hockey operations department. He later worked in the Coyotes' front office for two years and most recently served as assistant GM of the Canadian national team, which won gold at the 2023 world championship.
"The Maple Leafs have a such deep history and a passionate fan base, and I'm excited to contribute in any way I can in the organization's pursuit of their ultimate goal," Doan said in a statement. "I'm also thrilled to once again work alongside Brad Treliving and continue a working relationship that began during Brad's time with the Coyotes."