William was the son of Michael Steven Collins and Milley Jane Oliver. He was born on his father's farm in Holt County, Missouri. In 1875, his father bought a farm in the neighboring county of Atchison. There he operated a large fruit orchard. William spent most of his childhood on that farm. In 1892, his father purchased a farm in Valley County Nebraska and they moved there. In 1895, his father sold that farm and bought one near Hansen in Adams County, Nebraska. While there, his father hired a young girl named Eliza Vilmur to help in the house. She would become the wife of William on 19 Nov 1896 at O'Neill, Nebraska. The Ponca Indian lands up in Keya Paha County, Nebraska had opened up for homesteading so William filed for a homestead and they settled there. He built a sod house and also a frame house, as well as other buildings, on the homestead. They raised crops and animals. Sometimes they had unexpected visits from the local Indians

While there, they had three children, Arley Oliver, Clara Belle and Belle. Only one survived, Clara Belle. In 1902, they sold the homestead and moved back to Adams County, Nebraska. They had one more daughter, Mabel Ada (later known as Edith M.) William became ill shortly after she was born and he was hospitalized for the rest of his life. His wife went to work as a midwife in hospitals and private homes to support their daughters.

There is a discrepancy with William's date of birth. His father's Civil War Pension records dated 13 Nov 1912 says William was born in 1872 but William's Death Certificate filed in 1931 says the year was 1873. William's grave is unmarked but he is buried in the family plot near his mother, Milley J. Collins, at the Greenwood Cemetery near Hansen, Nebraska. The cemetery is adjacent to his father's farm.