Michael O'Neil (born May 29, 1951) is an actor who appeared in the JAG Season 4 episode, Shakedown (episode) as Commander Bradley and the JAG Season 10 series finale episode, Fair Winds and Following Seas (episode) as Major General Harold Rossing.
He later had a recurring role in NCIS as Riley McCallister and guest-starred in the NCIS: Los Angeles Season 13 episode, Indentured (episode) as retired Army General Richard Collins.
O'Neil also worked alongside Mark Harmon (Leroy Jethro Gibbs) in the TV series, "The West Wing", playing Secret Service Agents and as such, NCIS is the second TV series both men have worked alongside each other.