William was born at 'Penrose' (Te Paraetai), Masterton district. He was sheep farmer and breeder of Masterton. With his brother, Joseph William Perry, he founded the Lincoln flock at Penrose, followed by an English Leicester flock. Set up his Romney flock (1907), the sales of which set world records. On the management Committee of the Wairarapa Bush Rugby in 1909; President Masterton A & P Association; Farmers' Union; Meat Control Board 1923; director Wairarapa Frozen Meat Company 1923; 1st president Royal Agricultural Society 1924; 16 years chairman of the Wairarapa City Council; published on sheepfarming in NZ. He donated the land at Taratahi for an agricultural training centre.
He was knighted in 1933.

written 1897 Perry Brothers William and Joseph Walter Perry, Sheep Breeders and Farmers, "Penrose," Masterton. This well-known breeding farm was established in 1859 by the late Mr Bennett Pascoe Perry, one of Wellington's earliest settlers, who arrived in the Colony in 1841 and died in 1894. The property - about 3800 acres of land, which is very well suited for the breeding of stud Lincoln sheep, has been managed since 1882, when the late Mr Perry retired, by his two sons, who were brought up on the estate. Mr William Perry, the senior partner, was born on the farm in 1863, and received his education in Masterton. He is acknowledged to be an authority on Lincoln sheep and is frequently called upon to judge sheep at different shows throughout the North Island. A Lincoln ram bred on the farm gained first prize at the last Wellington show, beating the champion ram for Canterbury and Hastings shows. The sheep have also taken prizes at the various shows held in the district during the past few years. Mr William Perry was married to the eldest daughter of Mr William Bridson, late of the Native Department, Wellington and has one son. The late Mr Bennett Perry married a daughter of the late Mr Joseph Masters, after whom Masterton is named.

William married Margaret Jane Olive Bridson in 1891. He next married Olive 'Treve' Lipscombe (nee McKenzie 1888-1977) in 1942. Olive had 1st married Norman Langdale Newman (1888-1917) in 1912. She next married John Thackery Lipscomb (1862-1931) in 1919