(written from a Production point of view)
Crowley had a recurring role as Lou Welch in the first two seasons of the science fiction series Babylon 5, during which he co-starred with fellow Star Trek actors Mary Kay Adams, Michael Ansara, Jane Carr, Art Chudabala, Jeffrey Combs, Andreas Katsulas, Bill Mumy, Mark Rolston, Carel Struycken, Keith Szarabajka, Beth Toussaint, and Paul Winfield.
He has also co-starred with Star Trek: The Original Series actor William Shatner twice: first on an episode of T.J. Hooker (also starring James Darren and Richard Herd) in 1984, and then, twenty years later, in an episode of The Practice (with Stan Ivar and Bill Smitrovich). Other television series on which he appeared include Hill Street Blues (starring James B. Sikking, Barbara Bosson, and Megan Gallagher), Falcon Crest (with Robert Foxworth, Brett Cullen, and John McLiam), MacGyver (with Bruce McGill), Life Goes On (co-starring James Cromwell, Jordan Lund, David Selburg, and Bill Smitrovich), Picket Fences (with Ray Walston and Roy Brocksmith), NYPD Blue (co-starring Gordon Clapp, Sharon Lawrence, Janet MacLachlan, and Diane Salinger), Providence (with Michael Reilly Burke and Concetta Tomei), The Others (opposite Star Trek: Enterprise actors John Billingsley, Bill Cobbs, and Tucker Smallwood), The District (starring Roger Aaron Brown), The Guardian (with Kieran Mulroney and Raphael Sbarge), and The Agency (with Daniel Benzali, David Clennon, and Tim Kelleher).
On film, he appeared opposite Sylvester Stallone in 1982's First Blood (also featuring John McLiam) and with Tom Cruise and Star Trek V: The Final Frontier actor Laurence Luckinbill in 1988's Cocktail. He also had roles in the 1993 films Judgment Night and The Beverly Hillbillies.