She has also appeared in films such as Killer Movie (2008), Country Strong (2010), The Roommate (2011), Monte Carlo (2011), The Oranges (2011), The Judge (2014), The Weekend Away (2022), and EXmas (2023).

In 2009, she was featured as a guest vocalist on the Cobra Starship single "Good Girls Go Bad", which charted in the top ten on the Billboard Hot 100.

[6] Constance was able to give birth to Leighton in a hospital and nurse her for three months in a halfway house, before returning to prison to complete her sentence.

[12] Meester made her acting debut in 1999 as a murder victim's friend, Alyssa Turner, on an episode of Law & Order.

[13] Following this, she made her film debut as Elisha Springfield in Hangman's Curse (2003), based on the bestselling book by Frank Peretti.

[8] She then had guest roles on CSI: Miami[15] and Shark, and portrayed the female lead in the horror film Drive-Thru, for which she recorded the song "Inside the Black".

[25] Apart from Gossip Girl, Meester worked with co-star Ed Westwick in a Nikon Coolpix series camera advertisement, and both were the faces of the Korean clothing line ASK Enquired.

[24] Meester provided vocals on Cobra Starship's song "Good Girls Go Bad", which peaked at number seven on the Billboard Hot 100.

[30] Meester's first official single, "Somebody to Love", featuring R&B singer Robin Thicke, was released for airplay on October 13, 2009, and became available for digital download the following day.

Wesley Morris of The Boston Globe described Meester as the best part of the film, writing, "She's just doing Reese Witherspoon's June Carter Cash in Walk the Line with dabs of Miley Cyrus and Kellie Pickler.

"[46] Claudia Puig of USA Today was also positive, stating "Meester shows she can do more than play one of Gossip Girl's privileged Manhattan socialites.

[49] In October 2010, Meester said she had been working with a band called Check in the Dark and had been writing for the last six months after being inspired by Country Strong.

[51][52] In the same year, she took part in Bulgari's humanitarian efforts for the Save the Children organization with Isabella Rossellini and Maribel Verdú.

Entertainment Weekly found she was the only one to bring "the slightest trace of something fascinating to her role,"[59] while Los Angeles Times wrote, "[Meester's] performance often has the feeling of a sports car in neutral.

"[60] In the teen comedy film Monte Carlo, Meester portrayed Meg Kelly, Selena Gomez's stepsister and Katie Cassidy's friend.

[61] Movieline noted, "As in Country Strong, Meester's crack timing and irresistible poignancy illuminate a part that would leave other actresses simpering themselves off the screen.

[63] Meester's performance was again met with positive reviews, with the San Francisco Chronicle writing that she "succeeds in embodying all that is alluring and alarming about a 24-year-old woman.

[68] She next starred in the comedy film That's My Boy, alongside Adam Sandler, Andy Samberg, and Milo Ventimiglia, which was released in June 2012.

[73] She was unavailable to reprise her role as Carrie Bishop in the film Veronica Mars due to scheduling issues, and was replaced by singer Andrea Estella of the band Twin Sister.

[76] Meester made her Broadway debut in the stage adaptation of John Steinbeck's novel Of Mice and Men, starring opposite James Franco and Chris O'Dowd.

[79] Meester next appeared in Like Sunday, Like Rain directed by Frank Whaley, playing the girlfriend of Green Day's singer Billie Joe Armstrong,[80] and By the Gun, alongside Ben Barnes.

With its style compared to ethereal singer-songwriters such as Tori Amos and Joni Mitchell, the nine-song LP was written by Meester and produced by Jeff Trott.

[91] In January 2018, Meester joined the cast of Semper Fi, starring alongside Jai Courtney, Nat Wolff and Finn Wittrock,[92] which was released in October 2019.

[93] Meester starred in ABC's Single Parents alongside Taran Killam,[94] which premiered in September 2018[95] and was cancelled after two seasons.

In 2008, she was a spokesperson for Sunsilk's "Life Can't Wait" campaign, which aimed at motivating women to pursue their dreams.

[109] During her first two years working with Feeding America, she has volunteered at Los Angeles' Downtown Women's Center and assisted with relief efforts in Puerto Rico after Hurricane Maria in 2017.

"Together, we helped fill grocery baskets for families who lined up to receive important staples, like fruit, rice and cereal," Meester wrote in an Instagram post.

[116] Meester has graced the cover of numerous international fashion magazines, including US' Lucky, Flaunt, Shape, Nylon, Allure, Teen Vogue, Harper's Bazaar and Rolling Stone; Indonesia's Elle, Marie Claire, Cosmopolitan and CosmoGirl; UK's Company and InStyle; Morocco's L'Officiel; Australia's Cleo; Mexico's GQ and Seventeen; Russia's Elle Girl and Joy and Italy's Glamour.

Her mother also claimed that she was due a larger sum in return for "sacrificing her own happiness" when she moved Meester to Los Angeles as a child to pursue acting.

Constance accused her daughter of calling social services and fabricating a claim that she was abusing Alexander; investigators interviewed Meester and found no merit in the complaint.