Hudson began singing at age seven in her Chicago church choir. As a teenager, she performed at wedding receptions and in local talent shows and musical theatre. After graduating (1999) from Chicago's Dunbar Vocational Career Academy, Hudson attended Langston (Okla.) University. In 2001 she transferred to Kennedy-King College in Chicago to study music and appeared in a local musical production of Big River. Hudson then landed her first professional singing job on a Disney cruise ship as Calliope, the head Greek muse, in a 2003 production of Hercules: The Musical. Rather than renew her contract with Disney, Hudson decided to audition for American Idol, where she reached the final rounds before being eliminated in seventh place. After fulfilling her obligation to perform with the American Idol: Season Three tour during the summer of 2004, Hudson performed at charity events on Broadway and completed a concert tour throughout the Midwest.

During the summer of 2005, Hudson auditioned for Dreamgirls, a musical set in the 1960s about the rise and fall of a Motown group. She beat out more than 780 competitors, including third-season American Idol winner Fantasia Barrino, to secure the role. Hudson's powerful performance of the song “And I Am Telling You I'm Not Going” brought audiences to their feet in movie theatres across the country. Aside from her Academy Award, she received a Golden Globe Award, a Screen Actors Guild Award, the Sammy Davis, Jr. Award for entertainer of the year, and a British Academy of Film and Television Arts (BAFTA) Award. Hudson also appeared on the covers of many magazines, notably the March 2007 issue of Vogue, known as the annual “power issue.” She broke the fashion barrier as the most full-figured, curvaceous woman ever to have graced the magazine's cover.

In 2008 Hudson released her self-titled debut album and sang the national anthem at the Democratic National Convention at Barack Obama (Obama, Barack)'s request. That year she also appeared in the film sequel to the hit HBO show Sex and the City and in The Secret Life of Bees, alongside Queen Latifah. Despite widespread career success, Hudson's year took a tragic turn when her mother, brother, and nephew were found murdered in Chicago in October.