Cass began his career in the motion picture industry as an extra - but soon he was alternating between acting parts and stunt work. The stunt work eventually prevailed and Cass went on to become one of Hollywood's top stunt co-ordinators and Second Unit Directors. This led to his producing several films which, in turn, led to first-unit directing.

Dave has co-produced Miramax Films' Texas Rangers (2001); a trio of Burt Reynolds' TV movies titled Hard Time (1998), for the TNT network - writing one episode, and directing another, Hard Time: The Premonition (1999). He has also co-written several other films including Enter the Devil (1972) and Hard Ground (2003). Dave was the director of The Hallmark Channel's mini-series, Johnson County War (2002), another take on the infamous Wyoming cattle wars, this one an adaptation by Larry McMurtry. Cass has directed two Gentle Ben TV movies, plus Night of the Wolf (2002), starring Anne Archer and Robert Urich, for Animal Planet.

And from Hallmark, again, David directed a city girl/country boy love story, Straight from the Heart (2003), which garnered the highest ratings ever for a Hallmark Channel TV Movie.