Harron played Art Harris in the two-part The Outer Limits episode titled "The Inheritors" (1964), the Voyage to the Bottom of the Sea ("Doomsday", 1965) as the naval missile officer aboard the SSRN Seaview who could not bring himself to perform his duties to launch nuclear missiles and The Man from U.N.C.L.E. ("The Four-Steps Affair", also 1965) as an Australian U.N.C.L.E. agent named Kitt Kittridge. He guest-starred in the premiere episode of the television series Blue Light (1966), which was later edited together with the three following episodes to create the theatrical film I Deal in Danger. He made one appearance on the CBC Television show Adventures in Rainbow Country in the episode "The Frank Williams File" (1969). He has also been a host and interviewer on Canadian television and radio, hosting CBC Radio's Morningside from 1977 to 1982, for which he received an ACTRA Award for best radio host, and subsequently hosting an afternoon talk show, The Don Harron Show on CTV from 1983 to 1985. He had a featured role in Arthur Hiller's film The Hospital (1971), written by Paddy Chayevsky. Harron also appeared on The Red Green Show and replaced Gene Wood as host of the game show Anything You Can Do from 1972 to 1974.