2012–present: Continued success
On March 6, 2012, Britton signed on to star in and produce the ABC/CMT musical drama series, Nashville created by Academy Award winner Callie Khouri. The series ran on ABC and CMT for six seasons from October 10, 2012, to July 26, 2018. She played Rayna Jaymes, a 40-year-old renowned country singer whose stardom is beginning to fade. Britton's performance received critical praise, and she was nominated for a fourth time for a Primetime Emmy Award for Outstanding Lead Actress in a Drama Series and a Golden Globe Award for Best Actress – Television Series Drama for the first time for this role. Britton, for her part, said that the most nerve-wracking part of her role, at least in the beginning, was the singing the role requires of her. The show was cancelled in May 2016 by ABC. However, in June 2016, CMT picked up the series for a fifth season. In February 2017, Britton left Nashville during the fifth season, but returned for the series finale in July 2018 as a guest star.
In 2012, Britton co-starred opposite Edward Burns in the comedy-drama The Fitzgerald Family Christmas. The film was met with positive reviews from critics. That same year, she had co-starred in the comedy-drama Seeking a Friend for the End of the World opposite Steve Carell and Keira Knightley.
In 2013, Britton co-starred opposite Aubrey Plaza in the comedy The To Do List, where she played the mother of Plaza's character. Britton returned to Austin, Texas, where Friday Night Lights was filmed, to co-star opposite Harry Connick Jr. and fellow actors and musicians Willie Nelson, Lyle Lovett and Kris Kristofferson in the Christmas family drama Angels Sing. In 2014, Britton co-starred opposite Adam Driver as a cougar therapist in the comedy-drama This Is Where I Leave You, based on Jonathan Tropper's 2009 best-selling novel.
In 2015, she co-starred opposite Thomas Mann, RJ Cyler and Olivia Cooke in the comedy-drama Me and Earl and the Dying Girl, directed by Alfonso Gomez-Rejon, and based on Jesse Andrews' 2012 novel of the same name, a wry coming-of-age story about Greg (Mann), a teenage oddball forced to befriend Rachel (Cooke), a classmate with leukemia. She played Greg's mother. That same year, she co-starred in the action comedy American Ultra opposite Jesse Eisenberg and Kristen Stewart; Sharon Stone had originally been cast in her part.
In 2016, Britton reunited with American Horror Story creator Ryan Murphy in his miniseries American Crime Story: The People v. O.J. Simpson as Faye Resnick. In 2017, guest starred as Ally in the Showtime comedy series SMILF. Also in 2017, Britton starred in the comedy-drama film Beatriz at Dinner and the biographical drama Professor Marston and the Wonder Women. In 2018, she co-starred in the comedy-drama film The Land of Steady Habits.
Also in 2018, Britton starred as emergency dispatcher Abby Clark in the first season of the Fox procedural drama 9-1-1, her third collaboration with Ryan Murphy. The same year, she returned to American Horror Story for the eighth season, Apocalypse, reprising her role as Vivien Harmon. She also co-starred opposite Eric Bana as Debra Newell in the Bravo true crime anthology series Dirty John, for which she received a Golden Globe Award nomination for Best Actress – Miniseries or Television Film. In 2019, she played Roger Ailes' wife in the drama film, Bombshell. Her later film credits include Promising Young Woman (2020), Joe Bell (2020), Breaking (2022), and Luckiest Girl Alive (2022).
Britton starred as Nicole Mossbacher in the first season of HBO anthology series, The White Lotus in 2021, receiving Primetime Emmy Award for Outstanding Supporting Actress in a Limited or Anthology Series or Movie nomination (losing to her co-star Jennifer Coolidge). In 2023, she reunited with Friday Night Lights showrunner Jason Katims in the Apple TV+ drama series Dear Edward based on the novel of the same name by Ann Napolitano. In 2024, Britton appeared in the dark comedy film Winner playing the role of Reality Winner's mother.