He served in the cabinet from 1991 to 1999 overseeing various ministries, including a stint as Deputy Premier under Camille Thériault's leadership.
From 2004 to 2006 he served as chief of staff to New Brunswick MP Andy Scott in his role as Minister of Indian and Northern Affairs.
On September 20, 2006, Premier-designate of New Brunswick Shawn Graham appointed Tyler to chair his transition team.
In his first press conference as Premier on October 3, 2006, Shawn Graham said that Doug Tyler was serving as his acting chief of staff.
He was replaced by former cabinet colleague Bernard Thériault, who became Graham's first permanent chief of staff on October 30, 2006.