Karen Gillan was born and brought up in Inverness, Scotland. Her father, Raymond John Gillan, a Day Centre Manager, and mother, Marie Gillan née Paterson, live in Kinmylies. She learned to play the piano when she was seven. She has no brothers or sisters. At a young age, she developed a love for acting, joining several local youth theatre groups and taking part in a wide range of productions at her school, Charleston Academy. When she was sixteen, Gillan decided to use her interest in acting, studying at Edinburgh’s Telford College. Later, she got a place at the Italia Conti Academy of Theatre Arts drama school in London on the BA (Hons) Acting degree course. Gillan moved to London when she was 18 to study at drama school.

Before Gillan became an actress, she was scouted by a modelling agency. Gillan worked as a model in 2007′s London Fashion Week for designer Allegra Hicks’ autumn/winter catwalk show and the launch party of Nicola Roberts’ Dainty Doll Make-Up Range. This was shown in Roberts’ episode of the documentary, The Passions of Girls Aloud which premiered on 4 April 2008. Gillan has said she wouldn’t give up her acting career to return back to modelling. She stated that she enjoyed modelling but acting was always her main interest and goal.

Gillan’s early television acting career included guest appearances on several drama series, with her first ongoing role being a two-year stint as a member of the ensemble cast of the sketch comedy series The Kevin Bishop Show in which she played multiple characters, as well as celebrities such as Katy Perry and Angelina Jolie. She appeared in Channel 4′s ‘Stacked’; she had the part of Ginny.Gillan also appeared on TV in a leading role in a horror project entitled The Well, which was broadcast as a series of episodic short films on BBC Two, and then later also as a web series on BBC.co.uk. Part of the BBC’s multimedia “switch” programming, the short episodes interconnect with online games that further explore the environments presented in the series. She was cast for the role of the Eleventh Doctor’s first companion, Amy Pond, on the British sci-fi series Doctor Who in May 2009. She made her first on-screen appearance as Amy Pond in “The Eleventh Hour” with her cousin Caitlin Blackwood portraying a young Amy Pond. She was confirmed in Issue 420 of the Doctor Who Magazine to be appearing in the 2011 series. Gillan had appeared in Doctor Who once before in the 2008 episode “The Fires of Pompeii” in the role of a Soothsayer. Gillan made her first theatre appearance playing the role of Shirley in John Osborne’s play Inadmissible Evidence along with Douglas Hodge. The play debuted at the Donmar Warehouse on 16 October 2011. During August 2011, it was announced Gillan will star in an indie comedy called Not Another Happy Ending along with Emun Elliott. Filming will take place at the end of 2011 into early 2012. During an interview at the 2011 San Diego Comic-Con, Gillan revealed she will be returning to Doctor Who for its seventh series. On 15 December 2011, it was announced Gillan and Arthur Darvill (Rory Williams) would be leaving Doctor Who during the seventh series in 2012.[15] On 26 January 2012 Karen Gillan played the part of supermodel Jean Shrimpton in the BBC Four film, We’ll Take Manhattan which told the story of Shrimpton’s relationship with the photographer David Bailey. She has also been cast as Brittney in a re-working of Shakespeare’s Romeo and Juliet called Romeo & Brittney by David Baddiel.