Outside of Torchwood and Doctor Who, she is known for playing Sarah on Absolutely Fabulous, and the Spice Girls' pregnant friend Nicola in Spice World. She has also done voice-over work for the Genji video game series.
She also starred in a BBC Four play about the life and death of John Lennon, in which she played the musician's widow, Yoko Ono. John Lennon was played by Ninth Doctor actor Christopher Eccleston. It was broadcast in July 2010. In 2011, she reteamed with Torchwood guest star James Marsters in the pilot movie Three Inches, broadcast on Syfy.
Beginning in 2016, she reprised the role of Tosh in the Big Finish Torchwood series.
In 2018, Mori appeared as Yumiko in Mamma Mia! Here We Go Again.