Born on 26 March 1856, the son of John Massey, a Limavady farmer who left for better fortunes in New Zealand in 1862, William remained behind with relatives to complete his education. Eight years later, aged fourteen, he joined his parents in New Zealand. A contemporary described Massey as ‘bluff and hearty, thick set, and broad shouldered, of massive brow’. He had a strong work ethic and came to represent integrity in New Zealand politics. He often voted against a bonus for MPs. Massey started out, like many in public life at the time, on a road board. He went on to chair the local school committee and to lead the Auckland Agricultural and Pastoral Association. He fulfilled these roles so well that his peers and friends persuaded him to stand for parliament in 1893, when he was narrowly defeated. Three months later he was returned for Waitemata. In the following 1896 election he was returned for Franklin, securing a large majority. He held that seat until his death in 1925.