Gary O' Brien appears as a Voyager ensign inappropriately kissing another crewmember in a turbolift at the beginning of the Star Trek: Voyager episode "Elogium".

Gary O'Brien appears to have three pages at the Internet Movie Database ([1], [2], [3]). It is unknown if any of the listings on these pages besides his Voyager appearance is accurate, and his credits may indeed be spread across more pages.