Katherine Louise Stewart (born 30 November 1972)[1] is an Australian actress who has made numerous appearances in television series, movies and on-stage.

After graduation, I worked in publicity, but I couldn't shake my love of acting, so I enrolled at the National Theatre, hoping I'd outgrow it.

[6] The portrayal of Roberta Williams drew praise from critics including Marcus Casey of 'The Daily Telegraph', who described it as 'one of the most compelling performances by an Australian actress in memory.

'[4] Casey expanded that it was 'a brutally brave, ugly and compelling performance...She held nothing back, and was an emotional but controlled and screeching tornado who dominated the screen whenever the camera peered her way.

[9] In the series Stewart played the loveable but flawed, Nat Manning alongside Justine Clarke, Ben Mendelsohn, Matt Day and Catherine McClements.

[11] Stewart won many new fans in her role as Billie Proudman on Offspring, as part of an ensemble cast led by Asher Keddie and including John Waters, Eddie Perfect, Deborah Mailman, Richard Davies, Garry McDonald, Lachy Hulme and Linda Cropper.

[20] Writing in 'The Daily Telegraph', Colin Vickery reflected on season 7 with "this year...Billie, played by Kat Stewart, has had to endure a heartbreaking split with husband Mick (Eddie Perfect).

The pair played Charlie and Nicola Buchanan, a husband and wife duo of industrial cleaners with an amateur interest in solving crimes.

[24] In 2019, Stewart appeared in the Network Ten housemates' drama Five Bedrooms co-starring with Stephen Peacocke, Hugh Sheridan, Kate Jenkinson, Doris Younane and Roy Joseph.

[25] In an interview with Debi Enker of The Sydney Morning Herald, Stewart said of her character in Five Bedrooms, "Liz is brave, but also fragile.

[26] Reflecting on the show itself Stewart commented, "It’s a challenge to make TV that’s fresh and of the time, because we’re competing with such brilliant overseas content.

[27][28] [29] [30] Stewart's other TV credits include guest appearances in the Nazeem Hussain sketch comedy series Orange Is the New Brown in 2018,[31] True Story with Hamish & Andy on the Nine Network in 2017,[32] No Activity on Stan in 2015,[33] It's a Date[34] and Jack Irish: Dead Point in 2014,[35] Camp on America's NBC in 2013,[36] Miss Fisher's Murder Mysteries in 2012,[37] various roles in Newstopia on SBS in 2007–08, the BBC2/UKTV comedy series Supernova, as well as recurring roles on City Homicide, Kick, and Last Man Standing.

[38] Earlier in her career Stewart had guest roles on Blue Heelers, Stingers, CrashBurn, Something in the Air, The Secret Life of Us, and Fergus McPhail.

[39] In 2015, Stewart appeared with close friend and mentor Ailsa Piper in the contemporary interview program 'The Truth About Us' on Foxtel's Bio.

[40] In 2020, Stewart was one of the featured celebrities on the 11th season of the Australian version of the television documentary reality genealogy series Who Do You Think You Are?

The political satire was the first play from Australian filmmakers Working Dog Productions and the writing trio of Santo Cilauro, Tom Gleisner and Rob Sitch.

[48] In August 2016 she had a starring role on stage in the MTC production of the 2013 Pulitzer Prize winning play, Disgraced,[49] earning critical praise in the part of Emily.

[50][51] Stewart appeared in the 2019 Melbourne Theatre Company production of the Simon Stephens’ penned romantic comedy, Heisenberg.

[52] Stewart earned praise in the role of Georgie with Andrew Fuhrmann of the Herald Sun saying, "This new MTC production is elegantly done, with a slow, almost meditative rhythm.

"[53] In 2022, Stewart returned to the stage in the Melbourne Theatre Company production of Joshua Harmon's education satire Admissions.

[54] The production was directed by Gary Abrahams and co-starred William McKenna, Heidi Arena, Simon Maiden and Deidre Rubenstein.

[55] Cameron Woodhead of The Age described Stewart's performance as '...the glossiest possible portrayal of liberal officiousness and the cynical abyss her wokeness teeters into when the chips are down.

[60] In December 2020, Stewart co-hosted "How Big is My Trailer", an interview series bringing together two well known Australians in a "revealing and open-hearted conversation hour about the highs, lows and left turns of navigating a truly successful life in film, television and the arts.

"[61] Stewart co-hosted with Interviewer/Producer Angela Pulvirenti and each episode paired some of Australia's leading creative talents including George Miller with Tim Minchin, Asher Keddie with Daina Reid, Damon Herriman with Emma Freeman, Eric Bana with Trent Dalton, Eddie Perfect with Tina Arena.

[2] "My mum, Kitty, was the ultimate mother: fiercely protective, sometimes overinvolved, incredibly hospitable, very self-deprecating and oh-so stylish...Losing her felt catastrophic, but I've gotten to a point now where I feel grateful for having her at all.

[77] The cast of Offspring were also acknowledged with nominations for the Equity Awards for Outstanding Performance by an Ensemble in a Drama Series for 5 years running from 2011 to 2015[78][79] and again in 2017.