Together with parents and three older siblings, Holzinger came to the USA in 1921 and was naturalised as a US citizen in September 1940. He lived in Wisconsin and worked as a truckdriver. He joined the US army during the Second World War and went overseas as a member of troop ‘B’ 85th Cavalry Reconnaissance Squadron of the US 5th Armored Division. 

On the evening of Monday 11 September 1944, at around  18:00, Holzinger became the first US and allied soldier, as a staff sergeant, to put foot on mainland Germany. 

He led a foot reconnaissance patrol across the Our river. The patrol crossed over the remains of a destroyed bridge at Stolzembourg, Luxembourg and onto German soil. 

He was thereafter erroneously reported as being killed in action near Wallendorf. This was during the units participation in crossing the Sauer river and attacking German pillboxes. His reported death however, was not true. He survived the Second World War, returning home. Warner William Holzinger died on 5 June 1988 at the age of 72 in King, Wisconsin. He is buried at the Wisconsin Veteran Memorial Cemetery, King, Waupaca country, Wisconsin.