Collier attended the United States Military Academy, from which he graduated in 1918. Assigned to the Cavalry branch, Collier completed the Cavalry Officer Basic Course in 1920. Collier graduated from the Cavalry Regular Course in 1937, as well as the Advanced Equitation Course in 1938.
He was notable as a commander of 2nd Armored Division units in and as the Army’s Chief of Armor. He joined the Texas National Guard and served in the Villa Expedition. After receiving his commission, Collier was assigned to Europe to carry out an observation tour of World War I battlefields.
Collier served in assignments throughout the United States, including instructor at New Mexico Military Institute and postings to Fort
Riley, Kansas, Fort Benning, Georgia, and the Philippines. After graduating from the Command and General Staff College in 1941, Collier was assigned to the 2nd Armored Division for He served in Africa and Europe as commander of the division’s 3rd Battalion 66th Armored Regiment, and succeeded to command of Combat Command A when Maurice Rose was assigned to command the 3rd Armored Division.
He then commanded the 2nd Armored Division from June to September, 1945. Collier continued his service after, including high profile assignments as the Army’s Inspector of Armor, and commander of the United States. Army Armor Center and School.
After serving as the Chief of Armor, Collier assumed command of I Corps in of Korea on July 13, 1954.
In November he was assigned additional duty as interim deputy commander of the Eighth United States Army until the arrival of the permanent deputy commander, Lieutenant General Claude B. Ferenbaugh, in early January 1955. Ferenbaugh retired at the end of June and Collier relinquished command of I Corps to become deputy commander of Eighth Army and United States. Army Forces Far East.
He promptly made nationwide headlines when he attempted to prevent United States. service members from fraternizing with South Korean women, an effort that proved unsuccessful when commanders in areas outside Eighth Army control did not follow Collier"s example.
Collier returned to the United States in 1955 to assume command of the Fourth United States Army, where he served until his 1958 retirement. After his 1958 retirement, Collier resided in San Antonio, Texas, where he died 22 years later on April 21, 1980.
Collier was buried at Fort Sam Houston National Cemetery, Section M Site 105-C.