According to "The Forsythe-Humphrey Story" and "A Book of Memories", both written by his wife, William Henry Forsythe was the son of William Marion Forsyth and Margaret Scully. He is also mentioned as the grandson of Margaret Lurinda McFarland in her obituary. He was born on on February 25, 1893, at W. 2nd St., Galesburg, Knox County, Illinois. He died on July 8, 1974, in Resurrection Hospital, Chicago, Cook County, Illinois. He is buried in All Saints Cemetery, Des Plaines, Illinois.
When Bill was a small child he went by Willie Forsythe. Bill added the 'e' to the end of his name while in high school. Apparently his cousin Forrest J. Forsyth had gotten into some trouble, so Bill and his sister Edna wished to disassociate their names. Edna later removed the 'e'. It seems odd they would do this since they were the only Forsyth’s in the town of Galesburg at the time. I found Forrest's WW1 draft card, and there he has written his last name as Forsythe, so the above story is probably not true.
Bill attended Galesburg Public School, Corpus Christi Grade School, and Corpus Christi High School where he graduated June 2, 1911. After graduation, he worked for the Chicago, Burlington and Quincy (C.B. & Q.) Railroad, first as a timekeeper and pay-roll clerk, then as a switchman from 1913 to 1932. He was left go from the railroad during the depression and worked as a Metropolitan Insurance Agent in Galesburg, Illinois until 1941. Bill belonged to the Knights of Columbus in Galesburg, was a 4th Degree Knight, and played on the K.C. ball team. He also sang in the Glee Club and Church Choir. They moved to Chicago in 1942, where he found work once again as a switchman on the Milwaukee Railroad from October 1941 until he retired on October 20, 1959. From then on he did volunteer church missionary work in the St. Vincent de Paul Society of St. Mary of the Lake Church in Chicago, Illinois.

William Henry Forsythe and Minnie Elizabeth Humphrey were married on June 25, 1917, in Corpus Christi Church, Galesburg, Knox County, Illinois .