| Year | Title | Role | Notes |
| 1976 | NBC Special Treat | Julius | Episode: "Luke Was There" |
| 1977 | Blansky's Beauties | Anthony DeLuca | Main cast (13 episodes) |
| 1977–1984 | Happy Days | Chachi Arcola | Main cast (130 episodes) |
| 1977 | The Love Boat | Graham D. Pickrel II | Episode: "Ex Plus Y/Golden Agers/Graham and Kelly" |
| 1978 | The Runaways | Tommy | Episode: "No Prince for My Cinderella" |
| 1978–1979 | Who's Watching the Kids? | Frankie 'the Fox' Vitola | Main cast (11 episodes) |
| 1979 | Fantasy Island | Rob 'Robbie' Collins | Episode: "Amusement Park/Rock Stars" |
| 1980 | The Boy Who Drank Too Much | Buff Saunders | Movie |
| 1980 | Goodtime Girls | Tommy | Episode: "Growing Pains" |
| 1980 | Here's Boomer | Ronald | Episode: "Overboard" |
| 1980 | ABC Afterschool Special | Jack Melon | Episode: "Stoned" |
| 1981 | Senior Trip | Roger Ellis | Movie |
| 1982 | Gemini | Francis Geminiani | Movie |
| 1982–1983 | Joanie Loves Chachi | Chachi Arcola | Lead role (17 episodes) |
| 1983 | Hotel | Nick Tomasino | Episode: "Faith, Hope & Charity" |
| 1984 | CBS Schoolbreak Special | Buddy Elder | Episode: "All the Kids Do It" |
| 1984–1990 | Charles in Charge | Charles | Lead role (126 episodes); also director, 36 episodes, writer, 1 episode |
| 1985 | The Fall Guy | Merrick Thorson | Episode: "Femme Fatale" |
| 1985 | Alice in Wonderland | Pat the Pig | Movie |
| 1986 | The Truth About Alex | Brad Stevens | Movie |
| 1987 | Kids in Motion | Himself | Host |
| 1988 | My Two Dads | Scott Cameo | Episode: "She'll Get Over It" |
| 1988–1989 | Out of This World | Scott Gold / Prince Cornelius | 3 episodes; also director, 11 episodes |
| 1989 | Full House | Pete Bianco | Episode: "Dr. Dare Rides Again" |
| 1991 | Perry Mason: The Case of the Fatal Fashion | Asst. D.A. Peter Whelan | Movie |
| 1991–1992 | Baby Talk | James Halbrook | Main cast (23 episodes); also director, 1 episode |
| 1993 | Jack's Place | Woody B. King | Episode: "The Hands of Time" |
| 1993–1995 | Diagnosis: Murder | Dr. Jack Stewart | Main cast (41 episodes) |
| 1995 | Mixed Blessings | Charlie Winwood | Movie |
| 1996 | Can't Hurry Love | Matt | 2 episodes |
| 1997 | Rewind | Rob DiPaulo | Unaired series, 2 episodes |
| 1998 | The Nanny | Dr. Frankie Cresitelli | Episode: "Rash to Judgment" |
| 2000 | Veronica's Closet | Kevin | 2 episodes |
| 2000 | Bar Hopping | Damian | Movie |
| 2001 | Touched by an Angel | Frank McCovey | Episode: "A Death in the Family" |
| 2005–2013 | Arrested Development | Bob Loblaw | 5 episodes |
| 2006 | Van Stone: Tour of Duty | Lt. Perry | Movie |
| 2008 | Scott Baio Is 45...and Single | Himself | Reality (8 episodes) |
| 2008 | Finish Line | Frank Chase | Movie |
| 2009 | Confessions of a Teen Idol | Himself (host) | 8 episodes |
| 2012–2015 | See Dad Run | David Hobbs | Lead role (55 episodes); also executive Producer, 45 episodes |
| 2014 | Sam & Cat | Officer Kelvin | Episode: "#MagicATM" |
| 2014 | A Fairly Odd Summer | Foop (Human Form) | Movie |
