The son of a bank manager, Stephen Theobald was educated at the prestigious Haileybury School in Hertfordshire before going to Edinburgh University. A fine rugby player and cricketer at Haileybury, he once scored a century against Marlborough School at Lord’s. It was at hockey, however, that Theobald would go on to become an international, and he won his first Scotland cap during his time at university. A forward, either as a centre-forward or winger, Theobald toured South Africa with the Great Britain team in 1951 and the following year was a reserve to the Great Britain squad that won the bronze medal at the Helsinki Olympics. He played his club hockey with both Bristol and Devizes.