William was born in Ballarat, VIC in 1889 to William Horder and Elizabeth Jane Goodwin.

William was a building contractor or plumber in Bacchus Marsh, VIC when he enlisted in the AIF, 14^th Reinforcements, 8^th Battalion on the 18^th of August 1915, aged almost 27. He embarked aboard the HMAT A32 Themistocles in late January 1916, disembarking at Suez, Egypt in late February. In April he transferred to the 58^th Battalion where he was promoted to Lance Corporal a month later and embarked from Egypt in June, disembarking at Marseilles, France a few days later.

In August 1916 William was promoted to Corporal and then appointed temporary Sergeant a month later - confirmed as Sergeant in November. In February 1917 he suffered a gunshot wound to the left ankle and was admitted to the County of Middlesex War Hospital, suffering from inflammation of the connective tissue around the left heel. He was discharged from the 3^rd Australian Auxiliary Hospital, Dartford in August and rejoined his unit in France in late December. After a forced route march in April 1918, William developed two septic abscesses on his left ankle and was admitted to hospital in England. By August the wound had healed but was still tender. In December he embarked for Australia aboard the Somerset - septic traumatic abrasion to the left foot - returning to Australia in the middle of January 1919 and was discharged from the AIF in March.

William died in Bacchus Marsh, VIC in 1957, aged 68.

He is listed on the Roll of Honour for Bacchus Marsh and the Roll of Honour for the Bacchus Marsh ANA, held by the RSL at Bacchus Marsh and also on the Roll of Honour of S^t. Andrew's Presbyterian Church, Bacchus Marsh, held by the Bacchus Marsh Uniting Church.