Sergent’s acting career began at age 15 playing Lionel in the soap opera, Close to Home.
Brian is also known for playing Eric on the award winning television show, Outrageous Fortune (TV series), the New Zealand Prime Minister on The Flight of the Conchords (also named Brian), and Harold in The Lost Children (TV). One of his most popular characters, cabin steward Gavin Soper, appeared on the Pulp Comedy television series.
Sergent has a strong association with Circa Theatre in Wellington. He performed as five different characters in Time of My Life, ten roles in Greater Tuna, eleven characters in Travels with My Aunt and several roles in The Duchess of Malfi and Take a Chance on Me.
Sergent’s film credits include Peter Jackson’s Meet the Feebles, Braindead and Lord of the Rings, Absent Without Leave, Via Satellite, the lead role as Marty in The Shirt and Noah in Eagle vs. Shark.
Radio listeners are quite familiar with Segent's reading of short stories, novels and radio plays on Radio New Zealand where he is still actively involved.
Sergent won The Chapman Tripp theatre award in 2004 for most promising new playwright for his play The Love of Humankind.
He also won the Chapman Tripp theatre award in 1994 for male supporting actor of the year and the Chapman Tripp theatre award in 1992 for male actor of the year.
After taking a break from the show for nearly three years, Sergent returned to Outrageous Fortune as Eric in the second to last episode of the fifth season.
Television
2009: Flight of The Conchords (Prime Minister Bryan)
2005–06, 2009–10: Outrageous Fortune (Eric)
2006: The Lost Children (TV) (Harold)
2004: The Insiders Guide to Happiness: Is Happiness an Accident? (Father of the Bride)
2004: From Len Lye to Gollum [1] (narrator) (winner of 2005 qantas media awards best documentary)
2002: The Strip: Opening Night ('Dogwood' Douglas)
2002: The Strip: Epiphany ('Dogwood' Douglas)
2001: Shortland Street (Rich Fortune)
2000: Dark Knight (Phillipe de Mere)
1998: The Semisis: Episode #1.1 (Mr. Belton)
1997: The Legend of William Tell: The Spirit of Kale (Zark)
1996: Telly Laughs (Various Characters)
1993: Skitzo (Various Characters)
1992: The Ray Bradbury Theater: The Long Rain (Boltz)
1990: The Ray Bradbury Theater: Mars Is Heaven (Larson)
1990: The Armchair Shopper (host)
1986: Worzel Gummidge Down Under (Mildew Turnip), 1987 series 2 (Jeremy)
Guest star
Atlantis High: Mr Quentin/Q
The Insiders Guide to Happiness: (Is Happiness an Accident?) Father of the Bride
Dark Knight: (Ultimate Sword) Card Player #1
Atlantis High: Episode Seventeen (Mr Quentin Q)
Dark Knight: (Kha) Baron Phillipe de Mere
The Legend of William Tell: (The Spirit of Kale) Zark
Film
2015: Slow West (Peyote Joe)
2007: Eagle vs Shark (Jonah)
2003: The Lord of the Rings: The Return of the King (voices)
2002: Blessed
2001: The Lord of the Rings: The Fellowship of the Ring (extended edition) (Ted Sandyman)
2000: The Shirt (Marty)
1998: Via Satellite (Brian)
1996: Chicken (voices) (Orson Welles and James Mason)
1992: Heavenly Creatures
1992: Braindead (Vet)
1992: Absent Without Leave (Dick)
1989: Meet the Feebles (voice) (Wynyard the Frog, Trevor the Rat, F. W. Fly, Jim the Frog, Chuck the Frog, The Spider, Vietnamese Gophers)
1987: Footrot Flats: The Dog's Tale (voice) (Spit Murphy)
1982: Carry Me Back (Andy)
Short films
2002: Dying Light
1998: The Shirt
1992: I'm In Here
Theatre
2006: Dinner
2005: A Midsummer Night's Dream
2004: The Love Of Humankind (outstanding New Zealand playwright of the year)
2001: Othello
2001: Meltdown
2001: Speaking in Tongues
2001: Take A Chance On Me
2001: The Country Wife
1999: Shear Madness
1999: This Train I'm On
1998: Closer
1998: Four Cities
1998: The Big Picture
1997: Travels with My Aunt
1997: Lady Windermere's Fan
1996: Uncle Vanya
1996: Market Forces
1995: Moonlight
1994: I Hate Hamlet (Chappman Tripp award supporting actor of the year)
1994: Arsenic and Old Lace
1993: Ladies Night
1993: Summer of the Seventeenth Doll
1993: Arsenic and Old Lace
1993: A Dangerous Game
1992: The Homecoming (Chappman Tripp award actor of the year)
