Who plays Gamma in AMC's The Walking Dead?

The Walking Dead series ran for 11 seasons on AMC concluding its story in 2022.
Thora Birch as Gamma- The Walking Dead _ Season 10, Episode 8 - Photo Credit: Gene Page/AM8
Thora Birch as Gamma- The Walking Dead _ Season 10, Episode 8 - Photo Credit: Gene Page/AM8 /

Actress Thora Birch began her career at age 4 when she got her first role in a Quakers Oats commercial. She would appear in several commercials before receiving her first feature role in the 1988 sci-fi comedy Purple People Eater. This movie had an outstanding cast consisting of Neil Patrick Harris, Ned Beatty, Shelley Winters, Dustin Diamond, and Peggy Lipton, with musical cameos from Cubby Checker and Little Richard. She joined The Walking Dead in its tenth season as a character named Mary, aka Gamma.

Mary was a cunning and ruthless member of Alpha's (Samantha Morton) Whisperers who sacrificed her sister Frances (Juliet Brett) to prove her loyalty to Alpha. She quickly earned the leader's respect, who would put her in the No. 3 position and dub her Gamma.

Gamma eventually betrayed the Whisperers to learn of her nephew Adam, who was taken in by the Hilltop community. When she finds out that Alpha lied to the group about her daughter Lydia (Cassady McClincy), she arranges a deal with Aaron (Ross Marquand) to exchange information about the Whisperers in exchange for news about her nephew.

Ryan Hurst as Beta, Thora Birch as Gamma - The Walking Dead _ Season 10, Episode 13 - Photo Credit: Jace Downs/AMC /

During season 10, episode 12, "Walk With Us," Mary/Gamma sacrifices herself to save Alden (Callan McAuliffe), Kelly (Angel Theory), and baby Adam. She led a group of walkers away to ensure the group could escape. This is when she encounters the hulking Beta (Ryan Hurst), Alpha's No. 2, who seeks revenge for her betrayal. He stabs her, informing her that she will walk with them as part of the Whisperers' walker horde. When she tries to fight back, she rips part of his mask, enraging him, and he disembowels her. Beta waits for her to reanimate, and when she does, Alden shoots her in the head with an arrow, and Beta runs off before he can do the same to him.

Thora Birch - other roles

Her performance in Purple People Eater earned her the Young Artist Award for Best Actress Under Nine Years of Age. She would go on to become a child actor, appearing in many great titles, including Paradise (1991), Patriot Games (1992), Monkey Trouble (1994), Now and Then (1995), and Alaska (1996).

She is well known for her role as Dani Dennison, an 8-year-old who loves Halloween, in the holiday favorite Hocus Pocus. The film tells of three witches who, in the year 1693, were to be hanged for practicing witchcraft: Winifred (Bette Midler), Sarah (Sarah Jessica Parker), and Mary (Kathy Najimy), known as the Sanderson sisters. Before their hangings, Winifred casts a curse that will resurrect the sisters during a full moon on All Hallows' Eve if a virgin lights the Black Flame Candle. The film is set in 1993, when the sisters return to Salem and meet Dani and her friends.

In 1999, Birch entered her adult career phase, starring in American Beauty, for which she was nominated for that year's BAFTA for Best Supporting Actress. She then starred in the cult classic Ghost World with Scarlett Johansson and continued her career by starring in The Hole, Silver City, Dark Corners, and more. Next, she will appear in the second season of AMC's Anne Rice's Mayfair Witches as Gifford Mayfair. The series is expected to be released in the latter part of 2024.

Her directorial debut occurred in the Lifetime TV movie The Gabby Petito Story. In 2023, Deadline reported that Birch will see her feature directorial debut in an adaptation of Elmore Leonard's Mr. Paradise (2004). The story follows "Kelly, an aspiring model, witnesses a murder and gets caught in a web of intrigue."

She will be the first woman to direct a Leonard adaptation. The author is known for mastering hard-boiled crime novels, which have inspired the creation of Jackie Brown, Get Shorty, Out of Sight, 3:10 to Yuma, and the TV series Justified.


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