Born on 22 June 1872 at Todmorden, the sixth son of the Rev. Rennell Francis Wynn Molesworth, rector of Washington, Co Durham, and his second wife Frances Elizabeth, daughter of Admiral George Henderson, he was descended from Robert, first Viscount Molesworth (1656-1725), ambassador and politician. T H Molesworth was educated at Durham Grammar School and Caius College, Cambridge, where he took second-class honours in the Natural Sciences Tripos, part I, 1893. He qualified from St Bartholomew's Hospital in 1896, and served as senior house surgeon at Stockport Infirmary. During the South African War, 1899-1901, he was a civil surgeon with the field force. He was in general practice at Pembury and later at St Margaret's near Dover, where he was medical officer to the Portal House and Morley convalescent homes. He died at Priory Lodge, St Margaret's Bay on 10 April 1955 aged 82.