(written from a Production point of view)
Harelik made his television debut in the 1990 telefilm Unspeakable Acts, co-starring Bebe Neuwirth and Gregory Sierra. He went on to become a regular cast member for one season of the television series Hearts Afire, on which fellow Voyager guest star Leslie Jordan and Star Trek: Deep Space Nine guest actress Doren Fein also starred. He also had recurring roles on Wings, starring Steven Weber, and Veronica's Closet, starring Kirstie Alley. He also guest-starred in the final episode of Cheers (co-starring Kirstie Alley, Kelsey Grammer, and Bebe Neuwirth), and in 2005, he appeared in an episode of Numb3rs called "Toxins", which also guest-starred Star Trek: Enterprise actor Connor Trinneer.
In 1993, he co-starred with Enterprise guest star Joanna Cassidy in the telefilm Barbarians at the Gates (also featuring Ron Canada and Bruce French). He would go on to guest-star with Cassidy in an episode of HBO's Six Feet Under, also starring James Cromwell. Other TV shows Harelik has guest-starred on include Picket Fences (starring Ray Walston), Seinfeld (starring Jason Alexander), Desperate Housewives (starring Teri Hatcher, Mark Moses, and Steven Culp).
In 1994, Harelik, Steven Weber, and Steve Vinovich lent their voices to the animated film The Swan Princess. In 1999, Harelik assumed the recurring role of Jedidiah Lawrence on Boy Meets World, alongside Lindsay Ridgeway; the role of Jedidiah had previously been played by Michael McKean. Harelik went on to appear on-screen in the major motion pictures Election (1999), co-starring Matt Malloy, and Jurassic Park III (2001), which co-starred Enterprise actress Linda Park. He was also part of the ensemble cast of 2004's Eulogy, as were Rene Auberjonois and Famke Janssen.
In 2016, Harelik appeared alongside Ronald Guttman in the AMC series Preacher.