"I'm 20 years old. Is it a crime to go ... dancing with your friends?" the actress said Tuesday on "The Oprah Winfrey Show."
Lohan said she was "lucky and blessed" to be able to act.
"I've been acting my whole life and this is what I love to do," said Lohan, whose screen credits include "The Parent Trap," "Freaky Friday," "A Prairie Home Companion" and the upcoming "Bobby," about the 1968 assassination of Sen. Robert F. Kennedy.
Emilio Estevez, who directed the movie, told Winfrey that Lohan was a professional on the set, showed up on time and turned in "the best work of her life."
The media focuses on allegations of wild-child behavior "because it sells," Estevez said. "I'd rather have them focus on how extraordinary she is in this film," he said.
"Bobby," set for release Nov. 23, has an ensemble cast that also includes Demi Moore, Sharon Stone, Anthony Hopkins and Laurence Fishburne.
In July, James G. Robinson, chief executive officer of Morgan Creek Productions, chided Lohan in a letter for her behavior on the set of "Georgia Rule" and doubted her absence was related to heat exhaustion.
"We are well aware that your ongoing all-night, heavy partying is the real reason for your so-called 'exhaustion,"' he wrote.