(written from a Production point of view)
David Campagna (23 October 1946 – 6 March 2017; age 70) was an actor who appeared as a Q judge in the Star Trek: Voyager seventh season episode "Q2". As a background actor he received no credit for this appearance but was identified by a reference book. (Star Trek Encyclopedia (4th ed., vol. 2, p. 190))
After Campagna traveled through Europe in 1969, he decided to become an actor. He moved back to the United States and took acting classes at Ohlone College and Foothill College. He then moved to Los Angeles in 1973 and his first job in the industry was as an usher and page for ABC Television on the shows The Merv Griffin Show, Laverne & Shirley (co-starring David L. Lander and Michael McKean), The Odd Couple, and The Lawrence Welk Show.
Campagna was taught acting by coach Jeff Corey and was featured as a doctor on the daily soap General Hospital and played numerous bartenders and cops on television and film projects including the daily soap The Young and the Restless. In 1991, he performed in the play "On the Money" and in 1996, he played a truck driver – one of the first victims – in the horror film From Dusk Till Dawn, starring, executive produced, and written by Quentin Tarantino and with Fred Williamson, Marc Lawrence, Spice Williams-Crosby, and Rosine "Ace" Hatem. 
The 1995 crime drama Nick of Time was the first project on which he worked as stand-in and photo double for actor Christopher Walken. The film also featured Bill Smitrovich, C.J. Bau, Isabel Lorca, Greg Bronson, and Ray Uhler. During the next twenty years, Campagna worked as stand-in and photo double for Walken on over fifteen films including the romance Blast from the Past (1999, with Scott Thomson, Richard Gilbert-Hill, Annie O'Donnell, and Stephen Blackehart) and the comedy Kiss Toledo Goodbye (1999, with Robert Pine, Bill Smitrovich, David Drew Gallagher, and Johnny Martin).