Kromer was born in 1876 in Grand Rapids, Michigan. Kromer graduated from West Point in February 1899 and began his service as a commissioned officer in the 10th Cavalry Regiment. In 1901, Kromer was the head coach for the Army football team, with a record of 5 wins, 1 draw and 2 losses. The New York Times of 1930s noted that many contemporary U. S. Generals were connected by past football experience at West Point. Kromer also fenced for West Point against the Navy.
Military career
In 1918, Kromer served on the Western Front with the 82nd Division. According to his citation for the Distinguished Service Medal award, "As Assistant Chief of Staff of the 82d Division during the St. Mihiel offensive Colonel Kromer displayed military attainments of a high order in the planning of operations of great moment. Later as Assistant Chief of Staff, G-3, 1st Corps, and Assistant Chief of Staff, G-1, 1st Army, during the Meuse-Argonne operations, his initiative, sound judgment, and tireless energy solved difficult problems of traffic control and regulation, playing an important part in the successes achieved." In the beginning of 1934 Kromer was appointed Chief of Cavalry. His tour began with the 1934 field maneuvers involving Adna R. Chaffee, Jr.'s march from Fort Knox to Fort Riley, a demonstration of mechanized cavalry potential designed to determine how far cavalry had progressed to date. The future of cavalry was uncertain: it either remained the forward reconnaissance element of the Army, or had to develop into a completely new fighting force. Analysis of the maneuvers by Kromer's staff indicated that he seriously considered "marrying machine with the horse". He cautiously envisioned "combat cars assisting the horsed cavalry in closing with the enemy." In a foreword to the 1937 Cavalry Combat Kromer wrote that mobility was antithesis to static warfare; open flanks created by cavalry increased the magnitude of operations supported by horse troops. Only nine of 512 paged in this book were dedicated to mechanization, yet there is evidence that Kromer shared the opinion that if U. S. Cavalry did not mechanize it would disappear as a branch. Kromer was dissatisfied with the growing organizational rift between horse and mechanized elements of U. S. Cavalry, and redesigned the structure to close the gap. He endorsed expansion of mechanized units at Fort Knox although shortage of funds ruled out any massive changes. Kromer was an open-minded man who did not perceive mechanization as a threat to horse cavalry: "rather, he tried to adapt to a change and give each a role." By the end of his tenure Kromer embraced the modern concept of mechanized combat and, according to Robert W. Grow, "could have made cavalry the mechanized arm had he been supported by the army's General Staff and senior officers in his own branch."
In 1907, Kromer married Jane Miller Stotsenburg. Rosetta Kromer, Kromer's oldest daughter, was a concert pianist and was married to Wade D. Killen. His oldest son, John S. Kromer, was a West Point graduate who became an Episcopal clergyman. Another son, captain William A. Kromer, became a soldier and was killed in action in Europe January 1, 1945. Another son, Leon B. Kromer Jr., joined the Navy during World War II. After the war he headed industrial associations and served as labor relations advisor under presidents Kennedy, Johnson and Nixon. Daughter Jane Kromer, married Reverend C. D. Kean.
