He is well known for his recurring role during the first two seasons of the TV series Star Trek: Voyager, as First Maje Jal Culluh, leader of the Kazon-Nistrim.

[1] De Longis provided the voice of Marshal Leigh Johnson in the 2010 western video game, Red Dead Redemption.

He appeared as Claus Van Zandt in 1985 on the soap opera Days of Our Lives, and as Leo Mitchell in 1989 on Santa Barbara.

The initial productions presented swordplay for performance, but in 2002 branched out to include historically correct combative fencing techniques in conjunction with the Martinez Academy of Arms.

In 2015, De Longis appeared on an episode of MythBusters, teaching Adam Savage and Jamie Hyneman how to use a bullwhip so they could test Indiana Jones myths.

[4] In April 2023, De Longis returned to the show, prompting Rhett & Link to play a memory game revisiting the details of his initial appearance.