After Natalie [Wood] and I got back from our honeymoon, I began The Hunters, with Robert Mitchum, directed by Dick Powell. I adored both of them. Powell was one of the great guys of all time, and Mitchum and I became fast friends. He insisted that I call him "Mother Mitchum." One day we cooked up a juvenile practical joke—we hired a girl to sit on a bench at lunchtime without any underpants on. We were in Arizona, at an Air Force base, and from the reaction you'd have thought the men of the United States Air Force had never seen a woman's private parts before. As word spread, we gradually brought the entire base to a halt. The fact that it was juvenile didn't make it any less funny; actually, it made it funnier.

Evil's henchman Number 2 in all three films: Austin Powers: International Man of Mystery (1997) Austin Powers: The Spy Who Shagged Me (1999) and Austin Powers in Goldmember (2002). As Wagner is considered "a suave icon of American caper television including It Takes a Thief and Hart to Hart" Robert Glenister (Hustle's fixer Ash Morgan) commented that "to have one of the icons of that period involved is a great bonus for all of us". In 2005 Wagner became the television spokesman for the Senior Lending Network a reverse mortgage lender and in 2010 began as a spokesman for the Guardian First Funding Group also a reverse mortgage lender.

He also had a recurring role as Teddy Leopold on the TV sitcom Two and a Half Men. In movies Wagner is known for his role as Number Two in the Austin Powers trilogy of films (1997 1999 2002). Wagner's autobiography Pieces of My Heart: A Life written with author Scott Eyman was publiRobert Wagnerd on September 23 2008.