Buck was born on January 16, 1860, in Mayhew, Mississippi, to James and Martha Garner Buck. He graduated thirty of thirty-nine from the United States Military Academy class of 1885, alongside Willard Holbrook and Robert Bullard.

After graduation, Buck was commissioned as a Second Lieutenant in the Army's 16th Infantry Regiment and served frontier duty from 1885 to 1889. After completing a brief tour of duty in the Philippines, he returned to the United States to serve as commandant of cadets at Baylor University from 1893 to 1894. Upon the outbreak of the Spanish–American War in 1898, Buck entered the Second Texas Volunteer Infantry as a major and was honorably mustered out of the unit at the end of the war. On March 1, 1899, Buck was promoted to captain and became commandant of cadets at the University of Missouri, a position he held until 1902. During this period he completed three separate tours of duty in the Philippines during the Philippine–American War and married his wife Susanne Long on December 30, 1908. In 1914, Buck was promoted to the rank of colonel and sent to the US–Mexican border. A year later, he joined the Massachusetts National Guard.

On June 12, 1917, two months after the United States entered WWI, Buck became the commander of the 28th Infantry Regiment of the 1st Infantry Division. He was promoted to brigadier general on August 5 and given command of the 1st Division's 2nd Infantry Brigade, which he led during the battles of Cantigny and Soissons. Buck was awarded the Army Distinguished Service Cross for his role in the capture of Berzy-le-Sec, during which he "traversed the front of his advancing forces, gave correct directions to his organization commanders and led the first wave of the culminating attack which stormed and captured the town." He was promoted to Major General on August 8, 1918, and went on to command the 3rd Infantry Division and the 34th Infantry Division.

Buck returned to the United States on November 15, 1918, where he commanded Camp MacArthur in December 1918 and Camp Meade in March 1919. From May 1919 to March 1920 he was assigned to the Mexican–American border near Laredo, Texas, later transferred to Fort Crook in April 1920. His final assignment was as acting chief of staff of the 90th Infantry Division Organized Reserves at Camp Travis (now part of Fort Sam Houston) on August 15, 1921.

Buck retired from military service as a Colonel in 1924, moving to San Antonio, Texas. His full rank was restored by Congress in June 1930, and he published a memoir, entitled Memories of Peace and War, in 1935.

He died on February 10, 1950, and was buried in Fort Sam Houston National Cemetery in Texas.

Source of information: https://en.wikipedia.org