Peta graduated from NIDA in 2000.
Her other television credits include the television series All Saints, Last Man Standing, Jeopardy and Canal Road. Film credits include George of the Jungle 2 and The Bet (dir. Mark Lee) opposite Aiden Young, Matthew Newton and Sibylla Budd. She also featured in Early Checkout, and Kanowna.
She is currently playing the role of lil' kim in a translation of Serbian play Fake Porno directed by Bojana Novakovic.
Sergeant was critically acclaimed for her portrayal of a woman on the run in Steve Rodgers' play 'Savage River' for the Griffin Theatre Company. She also received praise as 'a stand out performance amid an excellent cast in Sue Smith's play 'Thrall'.
She has recently been cast as Nina Cruz in the Melbourne Theatre Company's production of All About My Mother, an adaptation for the stage based on the film by Pedro Almodóvar, directed by Helpmann award winning director Simon Phillips.
In 2012, she starred in one of the leading roles of Iron Sky, as Vivian Wagner: reelection-campaign advisor to a Sarah Palin-like president of the USA, who later becomes general on the US' interplanetary warship "USS George W. Bush".
Peta was born on Penang Island in Malaysia and moved to Australia at an early age. Her Irish/Australian father was raised on a farm in South Australia and joined the RAAF as a young man. It was as an RAAF officer stationed in Butterworth that he met Peta's mother.