Heyliger worked as a farm hand throughout his youth, and graduated from the Lawrence Academy at Groton in 1937. Heyliger completed three years of college where he served with the Army National Guard.
He took part in Doctorate-Day and Operation Market Garden. Heyliger was portrayed in the Home Box Office miniseries Band of Brothers by Stephen McCole. On November 25, 1940, he enlisted in the Air Corps (United States Army Air Corps) and trained as an aviation cadet before entering and graduating from Officer Candidate School.
In 1941, when the United States Army Air Corps was abolished as an organization and transformed into a branch subordinate to the United States. Army Air Forces (United States Army Air Force), Heyliger transferred to the United States Army and volunteered for the Paratroopers where he was eventually assigned to Easy Company.
After Richard Winters was promoted to Battalion Executive Officer (XO), First Lieutenant Heyliger took command of Easy Company from Winters" first replacement because that man failed to measure up. As First Lieutenant, Heyliger was in command of Easy Company during Operation Pegasus on October 23, 1944 and oversaw the rescue and evacuation of the some of the British 1st Airborne Division that were still stranded on the German side of the line after the failed Operation Market Garden across the Rhine.
He then underwent skin and nerve grafts before being discharged in February 1947. After Heyliger returned home to Massachusetts, he enrolled at the University of Massachusetts and graduated in 1950 with a degree in ornamental horticulture.
Heyliger died on November 3, 2001, in Concord, Massachusetts, at the age of 85, one day before the Band of Brothers miniseries aired its last episode.