[8] She lived in the same residence hall as filmmaker Christopher Nolan (her boyfriend and future husband),[9] whom she met when she was 18 during their first week at university.

[9] The first film that she produced was the short feature Doodlebug (1997), which depicts a man anxiously trying to kill a bug-like creature in his flat.

[11] After plans to create a full-length feature, Larry Mahoney, were scrapped,[12] Thomas produced her first feature, Following (1998), with Nolan and Jeremy Theobald, who stars as an unemployed young writer who follows strangers in London in hopes of receiving material for his first novel, but is drawn into a criminal underworld where he fails to keep his distance.

[15] The film was given a budget of $4.5 million (equivalent to $8,000,000 in 2023) and was distributed by Newmarket to 500 theatres in the United States after it was rejected by other studios, who feared that it would not attract a wide audience.

Thomas was credited as an associate producer of Memento, which received critical acclaim and several accolades, including two nominations at the 74th Academy Awards.

[24][25] The Dark Knight received eight nominations at the 81st Academy Awards, winning Best Sound Editing for Richard King and Best Supporting Actor; a posthumous accolade for Heath Ledger.

[27] During production of the Dark Knight trilogy, Thomas produced The Prestige (2006), an adaptation of the Christopher Priest novel about two rival 19th-century magicians, and Inception (2010), an original film about a professional thief who steals information by infiltrating the subconscious of his targets.

[32][33] Thomas's next feature Interstellar (2014), which she produced with Nolan and Lynda Obst, follows a group of astronauts who travel through a wormhole near Saturn in search of a new home for humankind.

It received positive reviews from film critics and was praised by astronauts for its scientific accuracy and portrayal of theoretical astrophysics.

[39] She and her husband were first interested in creating the film after taking an "ill-fated" sailing trip across the English Channel about twenty years prior, which "very much cemented for us what an incredible achievement that evacuation was".

It was a polarising screening for film critics; USA Today's Jenna Ryu and the Los Angeles Times' Christi Carras both described the overall tone of the reviews as "mixed" and "all over the place".

[61] Described as a "dream producer for both talent and studio" by Variety, Thomas' production sets are "notoriously harmonious", as they have consistently wrapped on schedule and on budget.

[6] Vanity Fair considers her to be her husband's "consigliere",[9] while Robbie Collin of The Telegraph regards her as the "driving force" behind the success of "cinema's most formidable power couple".

[10] She and Nolan were given the Spirit of the Industry Award from the National Association of Theatre Owners (NATO) in 2023 for making films that "shatter the limits of what cinematic storytelling can achieve, maintaining a shared passion and commitment to the theatrical filmgoing experience that is unwavering and unparalleled".

[65] At the same time as Nolan was knighted, Thomas was appointed Dame Commander of the Order of the British Empire (DBE) for services to film.