Julia Roberts made her film debut playing a supporting role opposite her brother, Eric, in Blood Red (she has just two words of dialogue), which, although filmed in 1987 was not released until 1989 (She was just about to have her 19th birthday during the filming). Her first television appearance was as a juvenile rape victim in the initial season of the series Crime Story with Dennis Farina, in the episode titled "The Survivor", broadcast on February 13, 1987. She also once appeared on Sesame Street opposite the character Elmo, demonstrating her ability to change emotions. Roberts first caught the attention of moviegoers with her performance in the independent film Mystic Pizza in 1988; that same year, she had a role in the fourth season finale of Miami Vice. The following year, she was featured in Steel Magnolias as a young bride battling diabetes and garnered her first Oscar nomination (as Best Supporting Actress) for her performance.

In 2001, Roberts received the Best Actress Oscar for her portrayal of Erin Brockovich, who helped wage a successful lawsuit against energy giant Pacific Gas & Electric. While presenting the Best Actor Award to Denzel Washington the following year, she made a gaffe, saying she was glad that Tom Conti wasn't there. She meant the conductor Bill Conti, who had tried to hasten the conclusion of her Oscar speech the previous year, but instead named the Scottish actor. Roberts would team up with Erin Brockovich director Steven Soderbergh for three more films: Ocean's Eleven (2001), Full Frontal (2002), and Ocean's Twelve (2004). Later in 2001 she starred in the road gangster comedy The Mexican giving her a chance to work with long time friend Brad Pitt. In 2005, she was featured in the music video for the hit single "Dreamgirl" by the Dave Matthews Band.

Roberts's two films released in 2006, The Ant Bully and Charlotte's Web, were both animated features for which she provided only voice acting. Her next film was Charlie Wilson's War, with Tom Hanks and Philip Seymour Hoffman, directed by Mike Nichols and based on the book by former CBS journalist George Crile; it was released on December 21, 2007. Fireflies in the Garden, also starring Ryan Reynolds and Willem Dafoe is currently in post-production, with release set for 2009. It has also been announced that Roberts will star in The Friday Night Knitting Club, based on the novel of the same name by Kate Jacobs. Her niece, Emma Roberts, is said to be considered for the role of her daughter.

• The Friday Night Knitting Club (2010) (announced) .... Georgia Walker
• Duplicity (2009) (completed) .... Claire Stenwick
  
• Fireflies in the Garden (2008) .... Lisa Waechter
• Charlie Wilson's War (2007) .... Joanne Herring
• Charlotte's Web (2006) (voice) .... Charlotte the Spider
  ... aka Schweinchen Wilbur und seine Freunde (Germany)
• The Ant Bully (2006) (voice) .... Hova
• Ocean's Twelve (2004) .... Tess Ocean
• Closer (2004/I) .... Anna
• Mona Lisa Smile (2003) .... Katherine Ann Watson
• "Freedom: A History of Us" .... Appleton;s Journal / ... (2 episodes, 2003)
       - What Is Freedom? (2003) TV episode .... Virginia Eyewitness
       - Yearning to Breathe Free (2003) TV episode .... Appleton;s Journal
• Full Frontal (2002) .... Catherine / Francesca
• Confessions of a Dangerous Mind (2002) .... Patricia Watson
  ... aka Geständnisse - Confessions of a dangerous Mind (Germany)
• Grand Champion (2002) .... Jolene
• Ocean's Eleven (2001) .... Tess Ocean
  ... aka 11 (USA: promotional abbreviation)
  ... aka O11 (USA: informal short title)
• America's Sweethearts (2001) .... Kathleen "Kiki" Harrison
• The Mexican (2001) .... Samantha Barzel
• Erin Brockovich (2000) .... Erin Brockovich
  
• Runaway Bride (1999) .... Maggie Carpenter
• Notting Hill (1999) .... Anna Scott
• "Law & Order" .... Katrina Ludlow (1 episode, 1999)
  ... aka Law & Order Prime (USA: informal title)
       - Empire (1999) TV episode .... Katrina Ludlow
• Stepmom (1998) .... Isabel Kelly
• Conspiracy Theory (1997) .... Alice Sutton
• My Best Friend's Wedding (1997) .... Julianne Potter