[2] At the age of 11, she joined the Vancouver children's musical theatre and later went on to tour Europe with the Magee Secondary School Choir in her senior year.

While living in Spain, Moss obtained a role as Tara, the clerk to Judge Nicholas Marshall in the drama series Dark Justice, her first television appearance.

Moss left Dark Justice before the series' third and final season and was replaced by Elisa Heinsohn as Samantha "Sam" Collins.

Many of her film roles in the decade were in B movies, including Flashfire (1994), The Soft Kill (1994), Tough Guy (1994), Lethal Tender (1996), Sabotage (1996), and The Secret Life of Algernon (1997).

It launched Moss into international recognition and transformed her career; in a New York Daily News interview, she stated, "The Matrix gave me so many opportunities.

In the romantic comedy Chocolat, she took on the role of Caroline Clairmont, a cold, devoutly pious woman living in a French village.

As part of an overall positive response towards the film, The New York Times remarked that Moss, "as an upright widowed mother swathed in mournful baby blue, radiates glimmers of hurt; she shows it's not easy to keep up such a front.

In Christopher Nolan's neo-noir psychological thriller Memento, she portrayed a manipulative bartender who meets a man suffering from anterograde amnesia.

Like the original, The Matrix Reloaded received positive critical reception,[14] and became a major box office hit, grossing US$742.1 million worldwide.

[16][17] During an interview with BBC Online, Moss expressed her pride for starring in the franchise, which she described as a "segment of [her] life": "It's deep and it's beautiful to have been part of it for so long.

In 2005, Moss starred in the little-seen thriller Suspect Zero as FBI agent Fran Kulok, and was part of an ensemble cast in the independent dramedy The Chumscrubber, which premiered at the Sundance Film Festival.

[23][24] She played one of the people who are brought together in the wake of a deadly car accident in the independent drama Normal (2007), released for selected theatres.

In the thriller Unthinkable (2010), directed by Gregor Jordan, Moss played the leader of an FBI counter-terrorism team assigned to interrogate a man who threatens to detonate three nuclear bombs in the United States.

[31] Writing for The New York Times, Mike Hale felt that Moss "feels out of place in this frontier tale, but looks great in snug wool suits".

[32] Moss obtained the role of Penelope, a California candidate for governor who runs a free health clinic, in the political thriller Knife Fight (2012), directed by Bill Guttentag.

In 2015, Moss appeared in Jessica Jones as Jeri Hogarth, an attorney and potentially powerful ally to the title character.

[39] Moss signed on to the series after reading the first two scripts, having been pitched the character by producer Jeph Loeb and screenwriter Melissa Rosenberg.

[41] Moss has also reprised her role of Jeri Hogarth in the second-season finale of Daredevil, and has had recurring arcs in Iron Fist and The Defenders.

Moss took on the lead role of Dr. Athena Morrow, an AI researcher invited to reverse engineer a consciousness program,[42] in the second season of the science-fiction series Humans.