He was the third son of Richard Child, 1st Earl Tylney, and Dorothy, daughter of John Glynne of Henley Park, Surrey.

Due to the inheritance, Richard Child and his sons all adopted the surname of Tylney in 1734, by private Act of Parliament, the Younger Sons of the Duke of Rutland's Names Act 1734 (8 Geo.

[1] John Child was educated at Westminster School in 1721 and later at Christ Church in Oxford.

[2] In 1765, he was a larger seated figure included in a caricature[5] painting by Thomas Patch.

[4][6] Patch was another Englishman living abroad and he had left Rome for Florence after he had been banished for a scandal based on his homosexuality.