He is best known for his involvement with Jim Henson and George Lucas through The Muppets, Sesame Street, and Star Wars, as well as his directorial work in feature films and theater.

Despite his interest in journalism, he continued his career as a puppeteer when he was hired by The Jim Henson Company in 1963, going on to perform several television characters such as Miss Piggy, Fozzie Bear, Animal, and Sam Eagle on The Muppet Show (1976–1981) and Cookie Monster, Bert, and Grover on Sesame Street (1969–2013).

Oz is also known for his work as a filmmaker, having directed the films The Dark Crystal (1982), The Muppets Take Manhattan (1984), Little Shop of Horrors (1986), Dirty Rotten Scoundrels (1988), What About Bob?

Oz was born Frank Richard Oznowicz[3] in Hereford on May 25, 1944, the son of Belgian mother Frances (née Ghevaert; 1910–1989) and Dutch-Polish father Isadore "Mike" Oznowicz (1916–1998), both of whom were puppeteers[4] who had moved to England when his father joined the Royal Netherlands Motorized Infantry Brigade.

[5][6][7][8] Some of his parents' puppets, including one that was made to mock Adolf Hitler, survived World War II and were presented at the Contemporary Jewish Museum[9] and the Dutch National Archives.

[20] His characters have included Miss Piggy, Fozzie Bear,[17] Animal, and Sam Eagle on The Muppet Show, and Cookie Monster, Bert and Grover on Sesame Street.

Oz performed as a puppeteer in over 75 productions, including Labyrinth (as the Wiseman), video releases, and television specials, as well as countless other public appearances, episodes of Sesame Street, and other Jim Henson series.

Oz voiced Yoda in the 2020 Oculus Quest virtual reality game Tales from the Galaxy's Edge alongside original C-3PO performer Anthony Daniels.

The musical film starred Rick Moranis and Ellen Greene, as well as Vincent Gardenia, Steve Martin, Bill Murray, John Candy, Christopher Guest, Jim Belushi and a 15-foot-tall talking plant (voiced by Levi Stubbs) which, at its ultimate size, required up to 60 puppeteers to operate.

Usually helming comedic productions, Oz went on to direct Dirty Rotten Scoundrels in 1988, starring Steve Martin and Michael Caine; What About Bob?

Later films include The Indian in the Cupboard (1995), In & Out (1997), Bowfinger (1999), The Score (2001), the 2004 remake of The Stepford Wives, and the original Death at a Funeral (2007).

Oz has frequently experienced on-set tension while directing his films, notably during the productions of What About Bob?, In & Out, The Score and The Stepford Wives.

[13][36][37][38] In 2016, Oz directed a one-man stage show titled In & Of Itself starring Derek DelGaudio, which had its world premiere at the Geffen Playhouse on May 16.

In October 2020, the streaming service Hulu purchased the rights to a live recording of the play, which debuted on January 22, 2021.

[47] In the late 1990s, it was reported that Oz was going to direct either Sylvester Stallone or Bruce Willis in an unmade film titled Ump for Metro-Goldwyn-Mayer.

"[53] In 2006, Dick Cook hired Oz to write and direct The Cheapest Muppet Movie Ever Made for Walt Disney Pictures.

[54][55] As an actor, Oz appeared in one scene as a Prison Storeroom Keeper in The Blues Brothers (1980), directed by John Landis.

He had roles in several other Landis films including An American Werewolf in London (1981), Spies Like Us (1985), Innocent Blood (1992), and Blues Brothers 2000 (1998).