With his wife, comedian Debra McGrath, Mochrie co-wrote, co-produced, and co-starred in the Canadian sitcoms Getting Along Famously and She's the Mayor.
He has written for numerous other series and events, and wrote and performed for the White House Correspondents' Association dinner.
[6] Upon graduation from Studio 58, Mochrie found his first line of work as a member of the Vancouver TheatreSports League.
Mochrie worked for The Second City for three years, co-writing and starring in three productions and directing three seasons of their national touring company.
As a member of the touring company, he performed in many skits, including one where he and two others are at a bar, and they help him to rewrite an anecdote from his youth involving his father taking him to a baseball game; and a five-minute version of a James Bond movie, complete with Mochrie in a downhill ski chase and parachuting off a cliff.
[11] He moved to Los Angeles the following year, but again auditioned for the British Whose Line, this time making the cut and being asked to fly to London.
[14] He believed his weak spots were the musical segments and the "Hoedown" game, which he said was the only time during the show when he felt total fear.
[10] In March 2005, a Nabisco advertising campaign starred Mochrie as the "Snack Fairy", in which he wears a ballet tutu over ordinary slacks and a shirt.
In an interview, it was revealed that in 1999 Mochrie worked on the Miloš Forman film Man on the Moon, but his scenes were deleted from the final movie.
In 2003, Mochrie, Leslie Nielsen, Wayne Gretzky, and Roy Halladay appeared in print and television advertisements to encourage people to visit Toronto after the SARS outbreak that struck the city.
He appeared on The Tonight Show with Jay Leno as the superhero Overly Sensitive Man (inspired by Whose Line).
In 2005, Mochrie appeared in "Burnt Toast", a series of eight comedic mini-operas, each depicting a different stage of a romantic relationship in a contemporary setting, produced by Canada's Rhombus Media.
Along with Rosie O'Donnell, Mochrie hosts a video introduction to a tour of the bakery in the Pacific Wharf area of Disney California Adventure Park.
In February 2007, he made a guest appearance as a priest in the seventh episode of Little Mosque on the Prairie, a Canadian television comedy series.
On March 28, 2007, Mochrie and his Whose Line costar Brad Sherwood hosted part of the Press Correspondents' Dinner with the President.
At that event, Sherwood and Mochrie featured Deputy White House Chief of Staff Karl Rove rapping.
On August 29, 2007, it was announced that Mochrie would host the Canadian version of the game show Are You Smarter than a 5th Grader?.
[19] On July 19, 2010, Mochrie starred as the divorce lawyer working on the case of Spinner and Emma in Degrassi Takes Manhattan.
In 2020 he hosted Mass Hysterical: A Comedic Cantata, a webcast collaboration between Second City alumni and the Toronto Symphony Orchestra which presented a comedic history of the use of classical and liturgical music in the church,[23] for which he received a Canadian Screen Award nomination for Best Lead Performance in a Web Program or Series at the 10th Canadian Screen Awards in 2022.
[24] He has appeared on the revival of sketch comedy series The Kids in the Hall, which was released on Amazon Prime Video on May 13, 2022.
[26][27] Mochrie and Whose Line co-star Brad Sherwood have intermittently toured North America as a two-man stage show since 2002.
Initially called "An Evening with Colin and Brad", they played primarily in small theatre venues.
As of 2018, Mochrie and Sherwood have continued their performances, billed as the "Scared Scriptless Tour", and are playing in larger venues such as the Sydney Opera House and London's Royal Albert Hall.
[30][31][32] In 2018, after Mochrie posted a picture with his wife and daughter on Facebook wishing her a happy birthday, he received hateful comments from trolls.