William Parker succeeded his father and became the 3rd Baron Parker of Shenstone Lodge at the age of 13 in 1902. Educated at Eton College, Parker went to Oxford University where he rowed for New College, but never won a rowing Blue. He was, however, a member of their eights that won the silver medal at the 1912 Stockholm Olympics.
Parker served as a captain in the 9th battalion of the Hampshire Regiment during World War I. He was mentioned in dispatches and subsequently awarded the OBE in 1919. A former Justice of the Peace (JP) for Hampshire and Breconshire, he served as the penultimate Lord Lieutenant of Brecknockshire between 1959-64. The office was abolished 10 years later. Parker died in 1971, just five months after Ruth, his wife of 56 years, passed away.