Wallin was born in
Washburn, North Dakota. Following brief attendance at the
University of North Dakota and a year in the state
National Guard, he was appointed to the
U.S. Naval Academy in 1913. He graduated in March 1917 and was commissioned in the rank of
Ensign. During most of
World War I, he served in the
battleship . In September 1918, he was transferred to the navy's Construction Corps and was sent to the
Massachusetts Institute of Technology for postgraduate education in
naval architecture. After receiving his Master of Science degree in 1921, Wallin served for four years at the
New York Navy Yard. He was assigned to the
Bureau of Construction and Repair in
Washington, D.C., in 1925 to 1929. Over the following decade he had successive tours at the
Mare Island and
Philadelphia Navy Yards and at the Bureau of Construction and Repair (redesignated the
Bureau of Ships in 1940). During this time, Wallin met and married his wife Elizabeth, and had two children, son Homer Norman, Jr. and daughter Susan Ann. In 1941, Captain Wallin became material officer for commander, Battle Force,
U.S. Pacific Fleet, and was serving in that position when
Japan attacked Pearl Harbor on December 7, 1941. Early in the following year, he was placed in charge of the
Pearl Harbor Navy Yard's Salvage Division. Through most of 1942, he directed the Pearl Harbor ship salvage effort, a huge task that enabled the navy to recover the use of three sunken battleships. From November 1942 to August 1943, he was force maintenance officer for the South Pacific Force, then spent a few months at the Bureau of Ships. Rear Admiral Wallin was supervisor of shipbuilding and inspector of ordnance at
Seattle and commander of the naval station at
Tacoma, Washington, beginning in October 1943. ==Post-World War II Career==