(written from a Production point of view)
Carmen Joseph "C.J." Bau (30 March 1937 – 30 April 2009; age 72) was the actor who portrayed the nightclub bartender in 1996's Star Trek: First Contact. His costume from this film was sold off on the It's A Wrap! sale and auction on eBay. 
Bau was born as oldest of three children in Pittston, Pennsylvania in 1937 and moved with his family to New York in 1949 where he graduated with honors from Cardinal Stepinac High School. After some time in the navy he started to work as an engineer and from 1960 on as a field service engineer for North American Phillips, Inc. In 1980 he retired and started to built on an acting career. Six years later he moved to Los Angeles.
Bau previously appeared in the independent film Obsessions (1987), the action thriller Sinners (1990, with stunt coordinator and 2nd unit director Michael J. Sarna), the action film Chance (1990, with Richard Allen and Cole S. McKay), the thriller Nick of Time (1995, with Bill Smitrovich, Isabel Garcia Lorca, and Ray Uhler), and in the Chicago Hope episode "The Virus" (1995, with Ken Jenkins and Caroline Lagerfelt).
Following his role in Star Trek: First Contact, Bau appeared in the short film A Guy Walks Into a Bar (1997, with Terrence Evans, Sean Whalen, and Robert Pine), the independent film Soulmates (1997, with Bill Cobbs and Debra Wilson), the short film Conversations (2004), and episodes of Dr. Quinn, Medicine Woman (1998, with Chad Allen, Barbara Babcock, Nicolas Coster, Don McManus, and Robert O'Reilly), L.A. Heat (1999, with Kenneth Tigar), Close to Home (2007, with Cress Williams and Richard McGonagle), and Leverage (2008, with Michael McGrady).