Chau was born to Vietnamese parents who lived in a refugee camp in Thailand after fleeing Vietnam in the late 1970s.

She grew up in New Orleans and majored in film studies at Boston University College of Communication before pursuing an acting career.

[2] In 1979, the family was among the Vietnamese boat people who fled their country, and Chau's mother was six months pregnant with her.

She said, "My whole life, I've always felt like I was the more acceptable of my parents, and they were always the people who had to stay in the background, or hide in the broom closet.

[23] Chau appeared in a supporting role as Ngoc Lan Tran, a Vietnamese political activist, in Alexander Payne's comedy-drama Downsizing (2017).

[24][25] Writing for Rolling Stone, Peter Travers described her performance as "nothing less than an acting triumph", and took particular note of her "poignant scenes" with the film's star Matt Damon.

"[29] In 2019, The Hollywood Reporter's Rebecca Sun said since Downsizing, "Chau has appeared in a series of critically acclaimed projects.

[31] Following the 2020 video-on-demand release of Driveways, Rolling Stone's Maria Fontoura wrote that Chau has a "cool tenacity" in her roles.

Fontoura said, "Whether she's playing a mysterious mogul, a secretive secretary, or a grieving single mother, the actress is steely, whip-smart, and deceptively powerful.

"[2] In May 2020, Chau had a larger role in Homecoming's second season, in which she moves from secretary to a person in charge in the series's featured corporation.

Lambe said, "What's notable about most of her projects is that they feature a diverse cast of actors of color who get to shine in unexpected ways," highlighting Treme, Watchmen, and Homecoming.

[37] Chau spent most of 2020 in lockdown due to the COVID-19 pandemic in the United States,[38] giving birth to a daughter in November of that year.

[38] For the drama The Whale, she was invited by its director Darren Aronofsky to audition for the role of Liz, a nurse.

[43] Matthew Creith of Out Front wrote, "The highlight of The Whale comes from an outstanding turn from Hong Chau, who gives a memorable performance in a vital role".

"[55] Chau appeared as a guest star in an episode of the Peacock TV series Poker Face, entitled "The Night Shift",[56] which premiered in January 2023.

[57] In March, Chau starred as Diane Farr, the White House chief of staff, in the Netflix thriller series The Night Agent.

[e] USA Today's Andrea Mandell said, "Hong Chau was snubbed ... a nomination many had assumed was a lock given the strength of her performance as a Vietnamese refugee.