(written from a Production point of view)
She made her acting debut in 1976, and in 1977 she played the lead role, Margaret "Muggsy" Malloy, in the television series Muggsy.
Her first television guest-starring appearance was in Murder, She Wrote in 1992. That episode, "The Wind Around the Tower", featured many other past and future Star Trek guest stars, including George Hearn, Mark Rolston, Richard Riehle, Dakin Matthews and Shay Duffin.
MacDonnell had a recurring role on Weird Science as Ms. Bouvier and appeared in Friends in the episode "The One with the Monkey". That episode also starred Wayne Péré. She later appeared in television movies such as Fatally Yours, Down, Out & Dangerous (also featuring Bruce Davison), Once You Meet a Stranger (also starring Neil Vipond) and The Areola.