Warning: Wikipedia contains spoilers
The film dramatizes the true story of a teenaged conman who stole over $4 million through forgery and other frauds, throughout a crime career lasting six years from 1963 to 1969. The film sticks closely to its protagonist's actual life story, as he reports it. Frank's impersonations typically served to gain him temporary prestige, as an airline pilot, doctor, or lawyer, as well as aiding him in cashing forged checks. He was caught by the FBI in 1969, and reduced his sentence by agreeing to assist FBI's bank fraud division by detecting forgeries and advising on countermeasures.
The movie was nominated for Academy Awards for Best Achievement in Music Written for Motion Pictures, Original Score and Best Performance by an Actor in a Supporting Role (Christopher Walken).