McGrath was born in Timmins, Ontario. His career began as Linus in the Montreal company of You’re a Good Man, Charlie Brown. He is known for his roles in Cheers as Andy Schroeder (the would-be strangler of Diane Chambers), Ozwald Valentine in Dallas, Dr. Benjamin Jeffcoate in My Secret Identity, Crewman Chell in Star Trek: Voyager, and as Dr. Derek Hebert in Doc. McGrath also played Buck the dog in a fantasy sequence in a second-season episode of Married… with Children, a game show host in a third-season episode of Family Matters, and a mutant in the 1993 comedy film Freaked. He appeared in a recurring role as the character of Anglican priest Duncan Magee in the CBC Television sitcom Little Mosque on the Prairie. He voices Spiff in the animated children’s series Iggy Arbuckle. He also voices Melvin, the mayor of Maple Lake in the animated series Bob & Doug. He also provided the voice of Heathcliff’s nemesis Spike in DIC’s Heathcliff and the Catillac Cats. He has also voiced various characters in Grossology, Pole Position, The Romance of Betty Boop, Intergalactic Thanksgiving, Bakugan Battle Brawlers, Super Why!, Wayside, Ruby Gloom, Toot and Puddle, Spliced, Jane and the Dragon and Take Me Up to the Ball Game. In 2002, he narrated the National Film Board of Canada short The Hungry Squid, which won the Genie Award for Best Animated Short. In the 1970s, he was a prominent actor on TVOntario educational programming, most notably Mathmakers.
He voices Mr. McFeely in Daniel Tiger’s Neighborhood and Chief Quimby in Inspector Gadget. He also played Garth Harble, Animal Control Officer, in the fifth season of The Red Green Show.
McGrath had a recurring role on Kim’s Convenience as Frank the handyman.
Derek will be appearing at NFCC FanFest BOTH DAYS.