Diablo Cody was born Brook Busey on July 14, 1978 in Lemont, Illinois, a suburb of Chicago, where she and her older brother Marc were also raised. She is the daughter of Pam and Greg Busey. Her mother is of Italian descent and her father is of German ancestry. Cody was raised Apostolic Christian and attended Benet Academy, a Roman Catholic school in Lisle, Illinois. At this time, she went by her birth name Brook.

In 2000, she graduated from the University of Iowa with a media studies degree. While at the University of Iowa, she worked in the acquisitions department in the main university library. Her first jobs were doing secretarial work at a Chicago law firm and later proofreading copy for advertisements that played on Twin Cities radio stations.

In March 2003, Cody started an adult blog called The Pussy Ranch, using a pen name invented while speeding through Cody, Wyoming listening to the song “El Diablo” by Arcadia. On a whim, Cody signed up for amateur night at a Minneapolis strip club called the Skyway Lounge. Having enjoyed the experience, and seeing reader interest, she eventually quit her day job to become a full-time stripper. Cody also spent time working peep shows at Sex World, a Minneapolis adult novelty and DVD store.

After completion of her book, Cody was encouraged by Mason Novick to try writing a screenplay. Within months she wrote Juno, a coming-of-age story about a teenager’s unplanned pregnancy. The script was completed in February 2005, and was optioned by a producer by that summer. The Jason Reitman-directed comedy stars Ellen Page and Michael Cera.

While still stripping, Cody began writing for City Pages, an alternative Twin Cities weekly newspaper. She left City Pages just before it changed editorial hands, and has since written for the now-defunct Jane magazine. In December 2007, Cody began writing a column for the magazine Entertainment Weekly.

The Juno script was read by many in Hollywood before the film was released, bringing Cody more opportunities. In July 2007, Showtime announced that it would be producing a pilot of Cody’s DreamWorks television series, United States of Tara. Based on an idea by Steven Spielberg, Tara is a comedy about a mother with dissociative identity disorder, starring Toni Collette. The series began filming in Spring 2008, and premiered on January 18, 2009.

In October 2007, Cody sold a script titled Girly Style to Universal Studios, and a horror script called Jennifer’s Body to Fox Atomic. Released on September 18, 2009, Jennifer’s Body starred Megan Fox as the title character and Amanda Seyfried as the supporting character. She revised writer-director Steven Antin’s script for his musical film Burlesque.

Cody made a small cameo appearance as herself in a 2008 episode of the television series 90210. She appeared in the same episode that marked the return of Tori Spelling as Donna Martin, in which Cody needed Spelling’s character to make a dress for a red carpet event. In 2009, Cody signed on to script and produce a film adaptation of the Sweet Valley High young adult book series. Diablo Cody is co-writing that the untold true story.

On April 6, 2010, Cody announced that she was expecting her first child with her husband Dan Maurio, who worked on Chelsea Lately, on which Cody also appeared frequently as a “roundtable” guest. The couple married in the summer of 2009. Their son was born in 2010. Cody had her second child in 2012. As of 2018, Cody and Maurio have three children.

In 2011, she was brought in to revise first-time feature director Fede Alvarez’s script for the remake of Sam Raimi’s 1980s horror film The Evil Dead. In October 2011, Cody began hosting an online celebrity interview program called “Red Band Trailer,” on the broadband channel, L-studio. She originally launched the series privately on YouTube in summer 2010, and the Lexus channel picked it up the following year.

In 2011, Cody wrote and produced the comedy-drama film Young Adult. Cody was nominated by awards associations such as the Broadcast Film Critics Association and the Writers Guild of America. With Jason Reitman, Charlize Theron and Patton Oswalt, she shared the Chairman’s Vanguard Award at the Palm Springs International Film Festival. In 2012, the Fempire, the collaboration of writers Cody, Dana Fox, Liz Meriwether, and Lorene Scafaria received the Creativity and Sisterhood Award from the Athena Film Festival for their support for one another in the competitive film industry.

On the WTF with Marc Maron podcast, on February 24, 2012, she said her next project would be directing her first film, which is about a young woman who abandons religion after surviving a plane crash. In February 2013, she announced that the film was called Paradise (firstly known as Lamb of God). Julianne Hough, Holly Hunter, Octavia Spencer, and Russell Brand starred in the cast. Mandate Pictures produced the film, which was released in October 2013.

In May 2013, it was announced that Cody would host her own talk show, Me Time with Diablo Cody, on TBS. The program would tailor “around Diablo’s unique perspective on all things pop culture and told in her very own tongue-in-cheek way,” and “reveal a side of Hollywood and celebs that the public very rarely gets to see.” Steve Agee was to be presenting and writing with her. Cody was a producer, alongside Mark Cronin and Courtland Cox. The series never materialized or made it to air.

She wrote the script for the Broadway musical Jagged Little Pill, based on the Alanis Morissette album of the same name. The musical premiered in November 2019.

In August 2020, Cody began working with Madonna on a screenplay of the singer’s life.