David Monahan (born August 13, 1971) is an American actor who guest-starred in the NCIS Season 1 episode, Sub Rosa (episode) as eco-terrorist Sean Travis. He also guest-starred in the NCIS: Los Angeles Season 1 episode, "Past Lives". Monahan's partner is Larry Sullivan who played the Flight Surgeon in the NCIS Season 1 episode, High Seas (episode) and the couple have an adopted child together.