Film •
Lone Star (1952) as Noah (uncredited) •
Crime and Punishment U.S.A. (1959) as Robert •
Home from the Hill (1960) as Theron Hunnicutt •
All the Fine Young Cannibals (1960) as Tony McDowall •
Where the Boys Are (1960) as Ryder Smith •
Angel Baby (1961) as Paul Strand •
By Love Possessed (1961) as Warren Winner •
A Thunder of Drums (1961) as Lt. Curtis McQuade •
The Light in the Piazza (1962) as Fabrizio Naccarelli •
Two Weeks in Another Town (1962) as Davie Drew •
The Victors (1963) as Cpl. Theodore Trower •
Act One (1963) as Moss Hart •
Looking for Love (1964) as himself (cameo) • ''
Your Cheatin' Heart'' (1964) as Hank Williams •
Viva Maria! (1965) as Flores •
That Man George (1966) as George • ''
Doctor, You've Got to Be Kidding!'' (1967) as Harlan Wycliff •
A Time for Killing (1967) as Capt. Dorrit Bentley •
Jack of Diamonds (1967) as Jeff Hill •
The Power (1968) as Prof. Jim Tanner •
Togetherness (1970) as Jack DuPont • ''
Elvis: That's the Way It Is'' (1970) as himself (uncredited) •
Evel Knievel (1971) as Evel Knievel •
The Man Who Loved Cat Dancing (1973) as Willard Crocker •
Medusa (1973) as Jeffrey •
Once Is Not Enough (1975) as David Milford •
The Happy Hooker Goes to Washington (1977) as Ward Thompson •
The Magnificent Hustle (1978) as Donald Hightower •
Sextette (1978) as Vance Norton •
From Hell to Victory (1979) as Maurice Bernard •
Love at First Bite (1979) as Count Vladimir Dracula •
Death Car on the Freeway (1979) as Ray Jeffries •
Zorro, The Gay Blade (1981) as Zorro The Gay Blade / Don Diego Vega / Bunny Wigglesworth •
The Godfather Part III (1990) as B. J. Harrison •
Doc Hollywood (1991) as Doctor Halberstrom •
Once Upon a Crime (1992) as Alfonso de la Pena •
Amore! (1993) as Rudolpho Carbonera •
Double Dragon (1994) as Channel 102 News Anchor (uncredited) •
Playback (1996) as Gil Braman •
Meet Wally Sparks (1997) as himself •
8 Heads in a Duffel Bag (1997) as Dick Bennett •
Bulworth (1998) as himself (uncredited) •
Casper Meets Wendy (1998) as Desmond Spellman • ''She's Too Tall'' (1999) as Alonso Palermo •
Off Key (2001) as Armand •
Crocodile Dundee in Los Angeles (2001) as himself (cameo) •
Reflections of Evil (2002) as Duncan Carlyle •
Hollywood Ending (2002) as Ed •
Pets (2002) as Von Steiger ('The Hand') •
The Little Unicorn (2002) as The Great Allonso •
The L.A. Riot Spectacular (2005) as The King of Beverly Hills •
Rumor Has It... (2005) as himself (cameo) (uncredited) •
Melvin Smarty (2012) as Hitman / Mexican Colonel •
Silver Skies (2015) as Phil •
The Congressman (2016) as Laird Devereaux •
Swiped (2018) as Phil Singer •
All Terrain (2022) as Graverly
Television •
The Donna Reed Show (one episode, 1959) as Herbie Shields •
The Rogues (one episode, 1964) as Jamie • ''
Burke's Law (TV series) Who Killed Mother Goose?'' (one episode, 1965) as Little John •
A Farewell to Arms (1966) (miniseries) as Lt. Frederick Henry • ''
Harold Robbins' The Survivors'' (1969) as Duncan Carlyle •
Paris 7000 (1970) (canceled after 10 episodes) as Jack Brennan •
The Last of the Powerseekers (1971) as Duncan Carlyle • ''
The Dead Don't Die'' (1975) as Don Drake •
Columbo: A Deadly State of Mind (1975) as Dr. Marcus Collier •
Roots (1977) (miniseries) as Stephen Bennett •
McCloud: The Great Taxicab Stampede (1977) as Keith Hampton •
The Strange Possession of Mrs. Oliver (1977) as Greg Oliver •
Killer on Board (1977) as Glenn Lyle •
The Users (1978) as Adam Baker •
The Eddie Capra Mysteries (1978 – Episode: "Nightmare at Pendragon Castle") as Leo Gerling •
The Seekers (1979) (miniseries) as Lt. Hamilton Stovall •
Institute for Revenge (1979) as Alan Roberto •
Express to Terror (1979) as David Belnik •
Death Car on the Freeway (1979) as Ray Jeffries •
The Great Cash Giveaway Getaway (1980) as Hightower •
The Fantastic Miss Piggy Show (1982) (TV special) as himself •
Malibu (1983) (miniseries) as Jay Pomerantz • ''
Two Fathers' Justice'' (1985) as Trent Bradley •
Dynasty (cast member from 1985 to 1986) as
Joel Abrigore •
Monte Carlo (1986) (miniseries) as Harry Price •
Spies (1987) as Ian Stone •
Poker Alice (1987) as Cousin John Moffit •
Columbo: Caution: Murder Can Be Hazardous to Your Health (1991) as Wade Anders •
The House on Sycamore Street (1992) as J.D. Gantry / Harry Lennox •
Birds of a Feather: It Happened in Hollywood (1993) as himself • '''' (1993) as Earl Henry von Hohenlodern •
Two Fathers: Justice for the Innocent (1994) as Bradley •
The Bold and the Beautiful (1994) •
George & Alana (1995–1996) as himself •
Vanished (1995) as Malcolm Patterson •
The Guilt (1996) as Alan Van Buren •
Hart to Hart: Till Death Do Us Hart (1996) as Karl Von Ostenberg •
Rough Riders (1997) (miniseries) as
William Randolph Hearst •
Miss USA &
Miss Universe (1997) as Host •
Jenny (1997–1998) as Guy Hathaway •
Baywatch (1 episode, 1999) as Earl •
P.T. Barnum (1999) as Francis Olmsted •
Nash Bridges (2000) as Raymond Peck •
The Family (2003) as Host •
Las Vegas (guest appearance 2004) as Bernard Taylor •
Too Cool for Christmas (2004) as Santa Claus •
Joey (2005) as himself •
Dancing with the Stars (2006) as Contestant • ''
I'm a Celebrity...Get Me Out of Here!'' (2009) as himself •
Comedy Central Roast of David Hasselhoff (2010) as himself – Roaster •
Hot in Cleveland (2013) as Robin •
Stewarts & Hamiltons (8 episodes, 2015) as himself •
Celebrity Wife Swap (1 episode, 2015) as himself •
2 Broke Girls (1 episode, 2016) as Bob •
American Housewife (recurring, 2017–2019) as Spencer Blitz •
General Hospital (July 6, 2018) as
Colonel Sanders •
Grace and Frankie (1 episode, 2019) as Jack Patterson ==Books==