What was the name of Frank Sinatra's only son?

Frank Sinatra’s only son was Frank Sinatra Jr.

Born Francis Wayne Sinatra on January 10, 1944, he was the second child of Frank Sinatra and Nancy Barbato Sinatra. His sisters were singer Nancy Sinatra and television producer Tina Sinatra. Although his father’s middle name was Albert, Frank Jr. became the name by which he was professionally known.

Frank Sinatra Jr. pursued a career in music as a singer, songwriter, conductor, and arranger. He eventually served as his father’s conductor and musical director, helping lead the orchestra during Frank Sinatra’s later performances. His career was often overshadowed by his father’s fame, but he continued performing for decades.

In December 1963, at age 19, he was kidnapped from a hotel at Lake Tahoe. He was released after his father paid a $240,000 ransom. Frank Sinatra Jr. died in 2016 at age 72. The names Robert, John, and Michael do not identify Sinatra’s only son.