Theodore Mavrogordato was educated at Westminster school before going to Oxford where he was a double Blue at tennis. He worked as a banker in the London city firm of P. P. Rodocanachie & Son and during World War I served as a Major in the Royal Army Service Corps (RASC). As a tennis player he had impressive CV, playing in the Davis Cup in 1914 and 1919. He was also selected in 1910 but the British Isles team was withdrawn, and he was a reserve in 1920. At Manchester in 1911 he won both the All–England mixed doubles, with his future wife [Mabel Parton], and the All-England men’s doubles titles, with the Australian Stanley Doust.
He was the Welsh Covered Court champion five times between 1905 and 1913 and twice won the Queen’s Covered Court tournament in 1912 and 1919. His best appearance in the singles at Wimbledon was in 1909, 1914 and 1920 when he reached the semi-finals. In 1920 Theo won the World Covered Court title at Queen’s Club with [Percival Davson]. He took part in all three indoor events at the 1912 Olympics, and in the mixed doubles partnered Mabel Parton (née Squire) who, 12 years later, would become Theo’s wife. Mavrogordato was a member of the LTA Council from 1913, was Chairman of the International Committee for two years and in 1930 was elected a Vice-President of the LTA. He died in his sleep in 1941 after returning home from duty with the Home Guard. He once lived at 18 Albion Street, London, the former home of novelist William Makepeace Thackeray. Sonia Mavrogordato, who played at Wimbledon in the 1930s, was Theodore’s niece, being the daughter of his brother George.