In her book, she wrote fondly of her boyfriend "Jonny" (musician Jon Hunt of Minneapolis psych-folk band, Lovely Dark). They were married from 2004 until 2007, during which time she was known in personal life as Brook Busey-Hunt.

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.

Juno was runner-up for the Toronto International Film Festival People's Choice Award, won second prize at the Rome Film Festival, and earned four Academy Award nominations, including one for Best Picture. Cody herself won an Academy Award for Best Original Screenplay for her debut script, which also picked up a Golden Globe nomination and an Independent Spirit Award for Best First Screenplay. She also won screenplay honors from BAFTA, the Writers Guild of America, the Broadcast Film Critics Association, the National Board of Review, the Satellite Awards, and the 2008 Cinema for Peace Award for Most Valuable Work of Director, Producer & Screenwriter (which she shared with Jason Reitman, John Malkovich, Mason Novick, Russel Smith and Lianne Halfon).

In 2009, Cody signed on to script and produce a film adaptation of the Sweet Valley High young adult book series. 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.

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.

Since October, 2011, Cody has hosted 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.

For Young Adult, Cody was nominated by awards associations such as the Broadcast Film Critics Association and the Writers Guild of America. With Reitman, the Director, and the actors 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.

In May 2013, it was announced that Cody will host her own talk show, Me Time with Diablo Cody, at TBS. The program will 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 will be presenting and writing with her as well. Cody is also a Producer, alongside Mark Cronin and Courtland Cox. The pilot of the talk show is in works.