The 5th SFG (A) traces its lineage to the 1st Battalion, 3rd Regiment, 1st Special Service Force, a combined Canadian-American organization which was constituted on 5 July 1942. It was activated four days later on 9 July at Fort William Henry Harrison, Montana. During World War II, the 1st Special Service Force was disbanded on 5 December 1944 in Villeneuve-Loubet, France.