Former fry cook Evelyn Candelaria filed a defamation lawsuit in New York accusing him of "ruining her life" after putting her in the movie without her consent.
The Oscar-nominated movie showed Spurlock eating only McDonalds meals for a month in a bid to show the detrimental effect of junk food on health.
Candeleria, 44, claims the film destroyed her reputation and self-esteem after she was portrayed as "incompetent, inept and incapable" while serving food.
Her lawyer Hugh Jasne said: "My reading of the law is that he needs to get a release form from her."
Spurlock recently signed up to make television and online productions for Fox TV Studios.