Aug. 6, 1818 Salem Washington County New York, USA
Oct. 28, 1888 Chicago Cook County Illinois, USA
William was the son of William McAllister and Hannah Shoulder.
William was admitted to the New York Bar, and moved to Chicago in 1854. He served as Judge Recorder's Court, 1st District from 1868 until August 8, 1870, at which time he was elected to the Illinois Supreme Court. He served on the high court until his resignation on November 26, 1875. After his tenure on the high court, he served as Cook County Circuit Court Judge from 1875 - 1888, and Appellate Court Judge in the 1st District from 1879 - 1888; posts which he held until his death.