Christina Applegate was born in Hollywood, California, to Nancy Priddy, an actress and singer, and Robert Applegate, a record producer. Her upbringing in the entertainment industry exposed her to acting from a young age, setting the stage for her future career.

At the age of 15, Applegate landed the role of Kelly Bundy, the stereotypical 'dumb blonde' daughter on the hit Fox sitcom 'Married... with Children'. This role catapulted her to fame, making her a household name and a teen idol. The show's long run cemented her status as a comedic actress.

While still appearing on 'Married... with Children,' Applegate began transitioning to film, taking on roles in movies like 'Don't Tell Mom the Babysitter's Dead' (1991) and 'Mars Attacks!' (1996). This period marked her effort to diversify her acting portfolio and showcase her range beyond sitcoms.

Applegate took on the lead role of Charity Hope Valentine in the Broadway revival of 'Sweet Charity.' While she initially injured her foot, causing some performance delays, she ultimately received positive reviews and solidified her presence in the theater world, demonstrating her talent as a singer and dancer.

Applegate starred in the ABC sitcom 'Samantha Who?', where she played a woman with amnesia who tries to rediscover her identity. She received critical acclaim for her performance, earning Emmy and Golden Globe nominations. The show further showcased her comedic abilities and established her as a leading lady in television comedy.

Applegate was diagnosed with breast cancer in 2008. She underwent a double mastectomy and has since become a vocal advocate for breast cancer awareness and early detection. Her openness about her experience has inspired many and raised awareness about the importance of preventative care.

Applegate starred in the Netflix dark comedy 'Dead to Me' alongside Linda Cardellini. Her performance as Jen Harding, a grieving widow with a dark secret, earned her widespread critical acclaim, including Emmy nominations. The show highlighted her ability to blend humor with emotional depth.

In 2021, Applegate publicly announced that she had been diagnosed with multiple sclerosis (MS). She has been open about the challenges she faces with the condition, and her bravery in sharing her experience has been met with support and admiration. She attended the Critics Choice Awards in 2023, walking with a cane, and received a standing ovation as she presented an award.