In November 2009, Colby was named an assistant editor of Maclean's, Canada's venerable general-interest newsmagazine. The appointment coincided approximately with the 30th anniversary of his first byline (a prize-winning schoolboy piece for what was then called the Sturgeon Gazette). His real writing career—give or take a few scattered appearances in the University of Alberta student newspaper The Gateway—began in 1992, with a stint as a researcher for the Alberta in the 20th Century series of history books. He went on to oversee the assigning and editing of Volume 8 of the history series, "The War That United The Province 1939-1945", and wrote some of it, including a long chapter on Bomber Command. He has also written chapters for the series about the grain-storage crisis of the 1950's (Vol. 9) and the postwar history of Canada's Indians (Vol. 10).

As a senior editor of the influential Alberta Report (1997-2003), he was an early practitioner of weblogging at his site ColbyCosh.com, blazing a trail for Canadian journalists. He later became a frequent contributor to the National Post newspaper and was a member of its editorial board from 2007-09. During his freelance years, he was also the sports columnist of the short-lived Western Standard magazine; made appearances in Canadian dailies such as the Calgary Herald, the Ottawa Citizen, and the Montreal Gazette; wrote for The American Spectator, the Los Angeles Times, and the The Comics Journal; occasionally appeared as a panelist and guest on the radio, including the BBC and at least a dozen CBC affiliates; gave live lectures on new media and other topics; and inflicted his face, always reluctantly, on viewers of CTS-TV's Michael Coren Show.

Colby was born in Edmonton in 1971 and grew up in the small town of Bon Accord, about twenty minutes' drive north of the city. He is a 1993 arts graduate (with distinction) of the University of Alberta and did post-graduate work in European intellectual history with the legendary libertarian scholar Ronald Hamowy. Today he shares his Edmonton home with two cats, Nigel and Eleanor.