[3] In February 2013 she was listed as one of the 100 most powerful women in the United Kingdom by Radio 4's Woman's Hour,[4] and in the same year she married fellow comedian Gary Delaney.

Millican was born and brought up in South Shields, England, the daughter of Valerie Prince and Philip D. King, who was a mining electrician.

[14] Millican has appeared as a panellist on 8 Out of 10 Cats, Have I Got News for You, Mock the Week, You Have Been Watching, Would I Lie to You?, QI and Never Mind the Buzzcocks, and as a performer at The Secret Policeman's Ball 2008 and on 4 Stands Up.

She provided vocal work to the BBC's natural history footage for Walk on the Wild Side, alongside fellow comics Rhod Gilbert, Jon Richardson, Isy Suttie and Gavin Webster.

[17] She appeared on Live at the Apollo on 11 December 2009, and headlined Michael McIntyre's Comedy Roadshow, recorded at the Empire Theatre, Sunderland on 15 August 2010.

[19] The format is that studio audience members are encouraged to share problems with her agony aunt character for her to offer tips "in the same way as the busybody at the end of your street who knows everything and dishes out advice whether you want to hear it or not does".

Some problems are scripted, the roles being played by guest actors, while others come from real people in the audience, to allow Sarah to improvise.

A pair of "therapists", also played by actors, feature in each week's show and provide scripted and improvised responses to all the "problems".

[21] She was a regular co-host of the satirical news show 7 Day Sunday on BBC Radio 5 Live, along with comedians Chris Addison, Andy Zaltzman and one different guest each week.

In December 2011, she voiced three Viz "Comedy Blaps" alongside Steve Coogan, Simon Greenall and Gavin Webster for Channel 4.

[23] The Chatterbox DVD went on to break an all-time record in sales for a female stand-up comedian selling 172,000 copies in just over one month.

[32] In lockdown during the COVID-19 pandemic in early 2020, Millican began uploading a series of videos entitled "How to Be Champion Storytime" in which she read a section of her autobiography every day.