(written from a Production point of view)
He played Culluh in five episodes of Star Trek: Voyager. He also lent his voice to two of Interplay Entertainment's Star Trek: The Original Series PC video games Star Trek: 25th Anniversary and Star Trek: Judgment Rites.
In 1987, he appeared in Masters of the Universe with Robert Duncan McNeill. In 1996, he appeared in an episode of Babylon 5 along with Rick Scarry, Bill Mumy, and Andreas Katsulas. In 1998 he starred in Sinbad: The Battle of the Dark Knights with Dean Stockwell and Star Trek: Deep Space Nine guest star Andrew Hawkes.
In addition to his acting career, De Longis is also a fight director, sword master, professional weapons trainer, horseman, and writer. He works as the fight director at the Los Angeles Music Center Opera, a position he's occupied since 1985. 
De Longis is also an instructor in professional stage movement and combat, having taught Michelle Pfeiffer whip handling for the movie Batman Returns, Angelica Houston for Buffalo Girls, and Ellen Barkin for Wild Bill.  Additionally, from 1974 to 1993, De Longis taught fencing, stage combat, and character movement at the Theater Arts Department at University of California, Los Angeles. 
As an experienced horseman, De Longis is a founding member of The Australian Light Horsemen, a "mounted cavalry team that performs realistic combat routines with sabers, lances, bullwhips, and pistols". 
De Longis has also been awarded with the Dramalogue Award for choreography in Mark Taper Forum's Julius Caesar. 
Appearances as Culluh
- The Sword and the Sorceror (1982; with Richard Lynch and Richard Moll)
- The Chipmunk Adventure (voice, 1987; with Frank Welker)
- CyberTracker II (1995; with John Kassir, Stephen Rowe, Stacie Foster, and Athena Massey)
- Masters of the Universe (1987; with Frank Langella, Meg Foster, and Robert Duncan McNeill)
- 1066 (2015; with Lee Arenberg and Matthias Hues)