Her first professional acting role at the age of 18 was Connie in the Liverpool sitcom Bread, which she filmed during her university studies. Early in her career, she teamed up with lifelong friend, Future Spaced star and Writer Jessica Hynes, in a comedy double-act called The Liz Hurleys. After leaving university, she began a TV career with the 1950s Liverpool drama And The Beat Goes On (1994), the Galton and Simpson series with Paul Merton, Wing and a Prayer, Death Of A Salesman, and Dennis Potter's Karaoke / Cold Lazarus. She played DC Jo McMullen in Liverpool 1.

On stage, she played opposite Steven Berkoff in his 3 hander Sturm and Drang and Brighton Beach Scumbags at the Riverside Studios (1995), Yseult -Whitehands with Kneehigh Theatres's international hit Tristan and Yseult (2005–06) (Sydney Festival, USA). Work at other theatres includes seasons at The Royal Exchange Theatre, The Liverpool Everyman, The Gate, and The Bristol Old Vic, where she met her Future husband actor Tristan Sturrock in a production of The Beaux Stratagem.

In 2001, Carmichael starred in her first film, Dead Babies, based on the novel by Martin Amis. She also appeared in Kenneth Branagh's comedy film In the Bleak Midwinter as mad puppetwoman and played the female lead Jane Wells in the period fantasy drama The Infinite Worlds of H. G. Wells. A variety of roles in comedy and drama followed; Hex, Scarlett, One Foot in the Grave, Clocking Off, Cutting It. In 2002, she landed the role of florist Lucy Richards in Coronation Street and was involved in the award-winning Peter Barlow bigamy storyline for two years. She went on to play Melissa Ryan (sister of headteacher Rachel Mason) school drama Waterloo Road (2007). Carmichael played the mother in Danny Stack's short supernatural thriller Origin (2010). In 2014, she played Helen the down-trodden housewife in Jimmy Mc Govern's series Moving On for the BBC and was Hayley Blake, Connie Beauchamp's nemesis in Casualty (2014–15). She plays Clarity Winlove in The Living and The Dead (2015).

Carmichael has been married to actor Tristan Sturrock since 2005. They have three children together: a son in born in 2004, a daughter born in 2006, and a second daughter born in 2010.

Carmichael collaborated with Bib-gourmand winning chef Matt Williamson and Guardian food Writer Claire Thomson to create the food-theatre show The Table Of Delights, which began as a gourmet tasting and performance experience for adults (Bristol Old Vic, 2013-2014). The children's version of the show premiered at The Print Room at The Old Coronet winning the Off West End award for best production for families category (2016). Carmichael is creative Director of The Table of Delights online a new food entertainment website sponsored by Yeo Valley and Pukka Tea.

In 2010, they set up Bristol based Theatre Damfino together. She has directed the company's projects to date including Mayday Mayday (Bristol Old Vic 2012) winner of the International Fringe Review award (Edinburgh 2012) and selected to play at St Ann's Warehouse New York and Spoleto festival USA (2013). Mayday Mayday is a drama documentary (afternoon play Radio 4 TX 1 May 2015). The Radio play won the International Third Coast award (USA) was nominated for two BBC Drama awards 2016 - best sound design and finalist for best drama production.

She directed singer and Songwriter Kate Dimbleby’s solo show Songbirds (Tobacco Factory, Bath Ustinov, UK Tour 2017) based on her acclaimed a cappella album.