John was the eldest son of Charles Evelyn, by Philippa Wright, the daughter of Fortunatus Wright, the privateer. Charles Evelyn was the only son of another Charles Evelyn, who was the brother of Sir John Evelyn, 2nd Baronet, and the second son of Sir John Evelyn, 1st Baronet of Wotton.
The elder Charles, of Yarlington, Somerset, died aged 40 in January 1748, while the younger Charles died before 1781. A lieutenant in the Portsmouth division of the Royal Marines, John killed a postman and was declared "of unsound mind" on 28 July 1795. He spent the rest of his life incarcerated.
John never married and on his death aged 75 at Bexhill-on-Sea on 14 May 1833, he was succeeded by his only surviving younger brother, Hugh.
