He was 7 when his father won writing and directing Oscars for "A Letter to Three Wives" and later recalled that "he always wanted to be in the business."
Mankiewicz majored in drama at Yale University and graduated in 1963.
For his first film credit, he went with Thomas F. Mankiewicz but decided it was too pompous and shortened it to Tom Mankiewicz, he later said.
He also wrote the book for the musical version of "Georgy Girl," which opened on Broadway in 1970. During its three-day run, "Bond" producer Albert R. "Cubby" Broccoli had been in the audience, looking for a rewrite man.
For years, Mankiewicz maintained a home in Kenya. He also owned thoroughbred racehorses and was chairman of the board of trustees of the Greater Los Angeles Zoo Assn.
His family was "quite close" but not necessarily "normal," he told The Times in 1987. "Our idea of affection isn't so much hugging each other as caressing each other with one-liners."
Since 2006, Mankiewicz had taught filmmaking to graduate students at Chapman University in Orange.
Most days, he ate lunch at the Palm in West Hollywood. As a memorial, the restaurant kept his booth open Monday night.
His father died at 83 in 1993.
Mankiewicz is survived by his brother Christopher, a producer and actor; his sister Alexandra; and his stepmother, Rosemary Mankiewicz.
Times staff writer Dennis McLellan contributed to this report.