He was the younger son of Richard Molyneux, 1st Viscount Molyneux and inherited the title from his elder brother, Richard Molyneux, 2nd Viscount Molyneux, in 1654.
He was the younger son of Richard Molyneux. He inherited the title from his elder brother 2nd Viscount Molyneux. This was in 1654. Richard Molyneux was his elder brother. Richard Molyneux was 1st Viscount Molyneux.