(written from a Production point of view)
Her first film role was a bit part as a nurse in the science fiction spoof Spaceballs, which also featured future Star Trek: Voyager star Tim Russ and Trek guest stars Dey Young and Leslie Bevis. She also appeared uncredited in the 1989 Blake Edwards comedy Skin Deep, co-starring Denise Crosby.
She has since had roles in various films, including Malice (1993), The Craft (1996), Black Dog (1998), The Deep End of the Ocean (1999, starring Whoopi Goldberg), and Red Dragon (2002). She also had roles in the hit 1997 science fiction film Starship Troopers (co-starring Star Trek Nemesis actress Dina Meyer and Trek guest actor Clancy Brown) and its 2004 direct-to-video sequel, Starship Troopers 2: Hero of the Federation (with Ed Lauter, Bobby C. King, Lawrence Monoson, and Nemesis stuntman Oliver Keller). She recently wrapped production on the independent drama You, co-starring John de Lancie and Jerry Hardin.
Strong, however, has enjoyed far more success on the small screen with recurring roles on several successful television series, including Party of Five, Seinfeld (starring Jason Alexander and with Armin Shimerman), Sports Night, 7th Heaven (starring Stephen Collins and Catherine Hicks, including one episode with TNG star Michael Dorn), and Everwood. She has also made guest appearances on such shows as St. Elsewhere, Cheers, Murphy Brown, Picket Fences, ER, The John Larroquette Show, 3rd Rock From the Sun, Ally McBeal, CSI (with Glenn Morshower), Nip/Tuck, Curb Your Enthusiasm, and Shark (starring Jeri Ryan, in an episode with Titus Welliver).
Her most famous television role, however, is one in which she is rarely seen, as Mary Alice Young, the deceased narrator on Desperate Housewives, the highly acclaimed drama series on which she worked from 2004 to 2012. A number of other Trek actors have appeared on the show as regulars and semi-regulars including Teri Hatcher, Steven Culp, Mark Moses, Alfre Woodard, Bob Gunton, Paul Dooley, and Scott Bakula. In 2011, Strong received a Primetime Emmy Award nomination for Outstanding Voice-Over Performance for the Desperate Housewives episode "Come On Over For Dinner" on which she worked with Teri Hatcher, Vanessa Williams, Kevin Rahm, and Tony Plana.
More recent appearances include guest roles in episodes of Scoundrels (2010, with Virginia Madsen, Jessica Collins, and Dina Meyer) and Rizzoli & Isles (2010, with Bruce McGill). She also portrayed Ann Ewing in the television revival of the soap opera Dallas (2013, with Marlene Forte). She has played Lillian Luthor in Supergirl since 2016.