Furst worked as a pizza delivery driver while looking for acting jobs in the mid-1970s, and included his head shot in pizza boxes.
After Matty Simmons saw his photo, Furst was cast as Kent "Flounder" Dorfman in National Lampoon's Animal House (1978).
He reprised this role in the short-lived 1979  spin-off TV series Delta House.
Others include 'Junior' Keller in The Unseen (1980), as Gonzer in the feature film Up the Creek (1984), as Dr. Elliot Axelrod in the television series St. Elsewhere (1983–1988), and as Vir Cotto in the science fiction television series Babylon 5 (1994–1998).
Furst was amused by the report that North Korean dictator Kim Jong Un modeled his haircut after Furst's character in Babylon 5.

In 1979 he played the role of an overweight high school tuba player coerced onto the wrestling team in Kieth Merrill's feel-good underdog film, Take Down.
Also in 1979, as pointed out above, he reprised the Flounder character in the ABC sitcom Delta House.
He also reprised the character and repeated his famous line, "Oh boy, is this great!"
in the Twisted Sister music video for "I Wanna Rock."

In 1980, he played the character of Harold in the movie, Midnight Madness, and the character of "Junior" Keller (the unseen) in the horror movie The Unseen.
In 1983, he also appeared in a supporting role as Aldo in the provocative ABC TV movie The Day After.
In 1989, he played the character of Albert Ianuzzi in the film The Dream Team.

In 1983, Furst also appeared in an episode of CHiPs titled "Fun House," alongside Erik Estrada, Tom Reilly, and Heather O'Rourke; in this installment, Furst acted out a student who belonged to the college fraternity "DDT."

In the 1995 animated TV series Freakazoid!,
he voiced the character Fanboy.
Also in 1995, he took a hiatus from Babylon 5 to star in a short-lived TV series, Misery Loves Company.
In 1997, he played Derby Ferris in Little Bigfoot 2: The Journey Home.
He also voiced a young Colonel Hathi in Season 2 of Disney's Jungle Cubs, had a starring voice role as Booster in the 2000 series Buzz Lightyear of Star Command, and also played a hulky walrus named Dash in the 2000 Disney movie The Little Mermaid II: Return to the Sea.
He starred in Magic Kid and its sequel.

In 2002, he guest starred in an episode of Scrubs.
In the same year, he was cast as Walter Nichols in the unaired pilot of the Nickelodeon television series Drake & Josh, but his identity was unknown in visuals, until his name was revealed in a YouTube video from 2017.
He was replaced by Jonathan Goldstein when the series was about to air, due to his being unavailable for future episodes.
Furst worked as a pizza delivery driver while looking for acting jobs in the mid-1970s, and included his head shot in pizza boxes. After Matty Simmons saw his photo, Furst was cast as Kent "Flounder" Dorfman in National Lampoon's Animal House (1978). He reprised this role in the short-lived 1979  spin-off TV series Delta House. Others include 'Junior' Keller in The Unseen (1980), as Gonzer in the feature film Up the Creek (1984), as Dr. Elliot Axelrod in the television series St. Elsewhere (1983–1988), and as Vir Cotto in the science fiction television series Babylon 5 (1994–1998). Furst was amused by the report that North Korean dictator Kim Jong Un modeled his haircut after Furst's character in Babylon 5.
In 1979 he played the role of an overweight high school tuba player coerced onto the wrestling team in Kieth Merrill's feel-good underdog film, Take Down. Also in 1979, as pointed out above, he reprised the Flounder character in the ABC sitcom Delta House. He also reprised the character and repeated his famous line, "Oh boy, is this great!" in the Twisted Sister music video for "I Wanna Rock."
In 1980, he played the character of Harold in the movie, Midnight Madness, and the character of "Junior" Keller (the unseen) in the horror movie The Unseen. In 1983, he also appeared in a supporting role as Aldo in the provocative ABC TV movie The Day After. In 1989, he played the character of Albert Ianuzzi in the film The Dream Team.
In 1983, Furst also appeared in an episode of CHiPs titled "Fun House," alongside Erik Estrada, Tom Reilly, and Heather O'Rourke; in this installment, Furst acted out a student who belonged to the college fraternity "DDT."
In the 1995 animated TV series Freakazoid!, he voiced the character Fanboy. Also in 1995, he took a hiatus from Babylon 5 to star in a short-lived TV series, Misery Loves Company. In 1997, he played Derby Ferris in Little Bigfoot 2: The Journey Home. He also voiced a young Colonel Hathi in Season 2 of Disney's Jungle Cubs, had a starring voice role as Booster in the 2000 series Buzz Lightyear of Star Command, and also played a hulky walrus named Dash in the 2000 Disney movie The Little Mermaid II: Return to the Sea. He starred in Magic Kid and its sequel.
In 2002, he guest starred in an episode of Scrubs. In the same year, he was cast as Walter Nichols in the unaired pilot of the Nickelodeon television series Drake & Josh, but his identity was unknown in visuals, until his name was revealed in a YouTube video from 2017. He was replaced by Jonathan Goldstein when the series was about to air, due to his being unavailable for future episodes.
Stephen Furst