McCune shot to fame in January 1994 when, at just 22 she was cast as Constable Maggie Doyle in Blue Heelers. She played the role until the seventh season, during which time she won the Gold Logie Award For Most Popular Television Personality four times. When her character was killed in 2000, the "Who Shot Maggie Doyle?" story arc was the most watched in the series history, and her departure is attributed as one of the major factors in the ratings slump that followed.
McCune followed up her television stint playing Mary Abacus in a telemovie adaptation of Bryce Courtenay's The Potato Factory (2000). Her next project, a "comeback" role in 2002, was the television series Marshall Law with Alison Whyte and former Blue Heelers cast member William McInnes. The series was critically panned, and ratings dropped significantly to ensure that it was cancelled after one season.
In 2004, McCune slowly began to return to television - first becoming the advertising face of Coles supermarkets, then hosting Seven Network shows such as The World Around Us and Forensic Investigators. McCune also starred alongside Matt Day in the ABC telemovie Hell Has Harbour Views.
In September 2005, McCune guest starred in a four-episode storyline on MDA alongside her former Blue Heelers co-star Paul Bishop. Also In 2005 she has narrated a second season of Forensic Investigators and was the Australian film Little Fish starring alongside Cate Blanchett and Sam Neill
McCune studied musical theatre at the West Australian Academy of Performing Arts (WAAPA) at Edith Cowan University, and has appeared in a number of musicals and other stage productions around Australia, notably as Sally Bowles in Cabaret and Maria in The Sound of Music.
She is married to Tim Disney, once part of the Blue Heelers crew, and has three young children, Archer, Oliver and Remy.