Bud Emmer was born on November 18, 1917, in Omaha, Nebraska. He enlisted in the Aviation Cadet Program of the U.S. Army Air Forces in January 1942, and was commissioned a 2d Lt and awarded his pilot wings at Luke Field, Arizona, on September 29, 1942. Lt Emmer served with the 20th Fighter Group at Paine Field, Washington, from September 1942 to January 1943, and then served as a P-39 Airacobra pilot with the 353rd Fighter Squadron of the 354th Fighter Group in the U.S. from January to November 1943. He then deployed with the 354th Fighter Group to England in November 1943 where they became the first American unit to operate the P-51. Capt Emmer flew on the first P-51 mission over Europe on December 1, 1943, and was eventually credited with the destruction of 14 enemy aircraft in aerial combat, 1 probable, and 2 damaged before being shot down by flak and taken as a Prisoner of War on August 9, 1944. Capt Emmer, badly burned in the explosion of his aircraft, received medical care and was then held in several POW camps, but died while still in captivity at Dulag Luft Wetzlar on February 15, 1945. He was buried in an Allied section at the cemetery in Bublinghausen, Germany. Later, in 1948, his and his brother's remains were returned from Europe to St. Louis, Missouri, where they were buried alongside each other at the New Mount Sinai Cemetery in Afton.

The Synopsis for his Distinguished Service Cross Citation reads:

For extraordinary heroism in connection with military operations against an armed enemy while serving as Pilot of a P-51 Fighter Airplane in the 353d Fighter Squadron, 354th Fighter Group, NINTH Air Force, in aerial combat against enemy forces on 26 July 1944, in the European Theater of Operations. On this day Captain Emmer destroyed two enemy aircraft and assisted in destruction of a third. Captain Emmer's unquestionable valor in aerial combat is in keeping with the highest traditions of the military service and reflects great credit upon himself, the 9th Air Force, and the United States Army Air Forces.