Megan Denise Fox was born on May 16, 1986, in Oak Ridge, Tennessee, the daughter of Franklin Thomas Fox, a parole officer, and Gloria Darlene Tonachio, a homemaker. Her parents divorced when she was three; she was raised primarily by her mother in Rockwood, Tennessee, and later in St. Petersburg, Florida, where her mother remarried. She began taking acting and dancing lessons at age five, attended the Morningside Academy, and began her professional acting career at age 13 with a small role in the Mary-Kate and Ashley Olsen film Holiday in the Sun (2001). She moved to Los Angeles and worked in small television roles — Confessions of a Teenage Drama Queen (2004) with Lindsay Lohan, Ocean Ave. — before auditioner for Michael Bay and being cast in Transformers (2007).
Transformers (2007) and Transformers: Revenge of the Fallen (2009) made Megan Fox one of the most prominent young actresses in Hollywood, her image deployed primarily as a visual spectacle in a franchise that used her with varying degrees of agency and dignity. The films placed her in the cultural consciousness in a specific way — as the quintessential Hollywood 'hot girl' — that had complicated consequences for her career and her public image. She has discussed in later interviews the ways in which the Transformers experience was psychologically damaging: she was subjected to intense sexualization from a very young age (she was 19 when filming began), and her public persona was shaped by the franchise's presentation of her in ways she found reductive.
Fox was fired from Transformers 3 after making public comments comparing Michael Bay's directing style to Hitler — comments she later acknowledged were poorly judged while maintaining that the working environment had been difficult. The period following her firing was professionally challenging, and she spoke publicly about severe anxiety, depression, and body dysmorphia during this time. She appeared in Jennifer's Body (2009, written by Diablo Cody, in which she played a cheerleader possessed by a demon who feeds on boys — a film that was initially commercially disappointing but has since developed a significant cult following, particularly among female audiences who appreciated its feminist horror sensibility) and in the Teenage Mutant Ninja Turtles franchise (2014, 2016).
In more recent years, Fox has been in a high-profile relationship with musician Machine Gun Kelly (born Colson Baker), whom she met during the filming of Midnight in the Switchgrass in 2020. She has become increasingly public about her spiritual practices — including past life regression, crystal work, and exploration of ayahuasca — and has been more openly vulnerable about her mental health history, her body image struggles, and the specific ways in which the film industry's treatment of her in her early career shaped her self-perception. She has three children from her marriage to actor Brian Austin Green (divorced 2021). Her public persona has evolved considerably from the Transformers era, and she has engaged with younger audiences through her self-presentation as someone navigating beauty standards, mental health, and spiritual seeking with a frankness that is unusual for someone with her level of conventional physical idealization.