Doug Welch completed and defended his PhD in Astronomy & Astrophysics from the University of Toronto in December 1985 and his degree was conferred in 1986. 

He engaged in postdoctoral work at the National Research Council's Herzberg Institute of Astrophysics' Dominion Astrophysical Observatory in Victoria, BC - first as an NSERC Visiting Fellow and then as a Research Associate. 

He joined the faculty in the Department of Physics at McMaster University in September 1988 as an NSERC University Research Fellow. He was Chair of the Department of Physics and Astronomy at McMaster between July 1997 and May 2000 and currently holds the rank of Professor. He is also Vice-Provost and Dean of Graduate Studies.

Doug Welch was the 2010 recipient of the McNeil Medal of the Royal Society of Canada. The medal is "awarded to a candidate who has demonstrated outstanding ability to promote and communicate science to students and the public within Canada (the term public is defined in its broadest sense)."

Doug Welch is  currently the Chair of the Board of Directors of the Canada-France-Hawaii Telescope Corporation. He is also a member of the Thirty Meter Telescope Board of Governors and Board Representative to its Science Advisory Committee.