Melanie Jayne Lynskey was born in New Plymouth, New Zealand, to Kay and Tim Lynskey. Growing up in a close-knit family, her early life provided a strong foundation for her future endeavors. Her upbringing in New Zealand instilled in her a down-to-earth personality, a trait often remarked upon by both fans and colleagues, and which perhaps helped her to avoid many pitfalls of fame.

At the age of 16, Lynskey landed her first professional acting role as Pauline Parker in Peter Jackson's critically acclaimed psychological drama 'Heavenly Creatures.' This marked a significant breakthrough for the young actress, showcasing her remarkable talent and establishing her as a rising star on the international stage. The film, based on a true story, also starred Kate Winslet and received widespread recognition, including an Academy Award nomination for Best Original Screenplay, setting the stage for Lynskey's burgeoning career.

Following the success of 'Heavenly Creatures,' Lynskey transitioned into a variety of supporting roles in films such as 'Ever After' (1998), 'Detroit Rock City' (1999), 'But I'm a Cheerleader' (1999), and 'Coyote Ugly' (2000). These roles allowed her to explore different genres and work alongside established actors, broadening her experience and solidifying her presence in the film industry.

Lynskey began making significant strides in television, notably with her role as Rose in the hugely popular CBS sitcom 'Two and a Half Men'. While initially a guest star, she would become a recurring one, playing the infatuated stalker character memorably for 12 years until the show ended. This marked a shift, finding her great success in TV shows and movies.

Melanie Lynskey married actor Jimmi Simpson in 2007. The pair would act together in several projects, including 'Rose Red,' 'It's Always Sunny in Philadelphia,' and 'Abraham Lincoln Vampire Hunter.' The pair would later divorce in 2014.

Melanie Lynskey began a relationship with actor Jason Ritter. After dating for 4 years, they were married in 2017. They have since appeared in several projects together and have one daughter together, born in 2018.

Lynskey continued to showcase her acting prowess in a string of critically acclaimed independent films. Her performance in 'Hello I Must Be Going' (2012) garnered widespread praise, and she delivered compelling performances in films such as 'Happy Christmas' (2014) and 'Digging for Fire' (2015). These roles allowed her to explore complex characters and further establish her reputation as a versatile and talented actress.

Lynskey's talent was again recognized when she was nominated for a Golden Globe Award for Best Actress – Television Series Musical or Comedy for her performance in the HBO series 'Togetherness.' This nomination underscored her growing prominence in the television industry and solidified her status as a leading actress.

Lynskey landed a starring role in the critically acclaimed Showtime series 'Yellowjackets,' playing the adult Shauna Shipman. The show, a mix of survival drama and psychological thriller, has garnered significant attention and praise for its cast, particularly Lynskey's performance. This role brought her renewed recognition and critical acclaim, earning her nominations for a Primetime Emmy Award and Critics' Choice Television Award, which she won. The series has proven to be a massive success and secured Lynskey a place as a household name.