She gained recognition for her roles in the comedy series The Book Group (2002–2003), Green Wing (2004–2007), and Bad Education (2012–2013).

She went on to appear as Missy in the long-running British science fiction series Doctor Who (2014–2017), for which she was nominated for the BAFTA TV Award for Best Supporting Actress.

Gomez's first major role was in the 1998 film The Acid House, based on three Irvine Welsh short stories.

In 2014, she began producing comedy sketches as "Heather" an agony aunt for YouTube channel Wildseed Studios.

Her true identity was revealed in the Series 8 two-part finale "Dark Water" / "Death in Heaven" as an incarnation of the Master, the Doctor's longstanding nemesis.

[11] In 2018, Gomez was cast as Lilith / Madam Satan and Mary Wardwell in the Netflix series Chilling Adventures of Sabrina.

[12] She later appeared as Miranda Croft in the HBO Max dark comedy thriller series The Flight Attendant in November 2020.