Arena graduated from the National Institute of Dramatic Art in 2003 and has since had many roles in television and theatre. She has two children with her art director husband Mick, a daughter Dora and a son Miles. 
Arena plays the wheelchair bound deputy head librarian Dawn in the ABC series The Librarians, created Wayne Hope and Robyn Butler. Arena was eight months pregnant when she first appeared in the show. She plays the eponymous host of the satirical cooking show Audrey's Kitchen which screened in 2012 and 2013.  The show, created by Working Dog Productions, stars Arena as Audrey Gordon, a fictional celebrity chef whose style is described as "Delia Smith meets Nigella Lawson".
Arena is a core cast member of the improvisational comedy Thank God You're Here and has appeared in a recurring role in the drama series Blue Heelers as Captain Marissa Craddock in 2003 and 2004. She had supporting roles in the comedy drama series Last Man Standing and the children's drama series Nowhere Boys in 2013 and The Worst Year Of My Life - Again! in 2014.
- Priest, Annika (17 January 2013), "Heidi Arena casts off wheelchair to take theatre, television roles", Melbourne Leader
- Jack, Victoria (31 July 2009), "Satirising stereotypes", The Newcastle Herald
- Taffel, Jacqui (29 October 2007), "Have a lend of us", The Sydney Morning Herald
- Yeap, Sue (13 July 2012), "Quirky chef has catchy manner", The West Australian
- "Thank God it’s back", Kalgoorlie Miner, 3 April 2009
- "Standing up to male hedonists", Sunday Herald Sun, 12 June 2005
- Woodhead, Cameron (23 January 2010), "Rush shines in deliriously catchy nostalgia musical", The Age
- Herbert, Kate (4 February 2013), "Poignant portrayal of a cruel disease", Herald Sun
- Rose, Kate (31 May 2009), "Burlesque romps with the surreal", Sunday Herald Sun