He had enlisted in the Army. Served during World War II. He had the rank of Private First Class. Service number was 31284990. Served with 5307th Composite Unit. This is the predecessor of the modern day 75th Ranger Regiment.
Merrill’s Marauders (named after Frank Merrill) or Unit Galahad, officially named the 5307th Composite Unit (Provisional), was a United States Army long range penetration special operations jungle warfare unit, which fought in the South-East Asian theatre of World War II, or China-Burma-India Theater (CBI). The unit became famous for its deep-penetration missions behind Japanese lines, often engaging Japanese forces superior in number.

U.S., Headstone and Interment Records for U.S., Military Cemeteries on Foreign Soil, 1942-1949
Name: Donald R. Adams
Rank: Private First Class
Residence Place: Massachusetts
Service Number: 31284990
Military Branch: U.S. Army
War: World War II
Cemetery: Manila American Cemetery
Burial Place: Manila, Philippines

U.S., World War II Hospital Admission Card Files, 1942-1954
Name: Donald R Adams
Rank: Enlisted Man
Admission Age: 21
Birth Date: abt 1923
Admission Date: Jun 1944
Discharge Date: Jun 1944
Military Branch: Infantry, General or Unspecified
Diagnosis: First Location: Unknown, code not applicable; Causative Agent: None or Unknown
Type of Injury: Casualty, battle
Injured in Line of Duty: In line of duty
Type of Discharge: Died
Length of service: 1 Year(s), 3 Month(s)
Service Number: 31284990

U.S., World War II Army Enlistment Records, 1938-1946
Name: Donald R Adams
Race: White
Marital status: Single, without dependents (Single)
Rank: Private
Birth Year: 1923
Nativity State or Country: Massachusetts
Citizenship: Citizen
Residence: Hampden, Massachusetts
Education: 3 years of high school
Civil Occupation: General industry clerks
Enlistment Date: 18 Feb 1943
Enlistment Place: Springfield, Massachusetts
Service Number: 31284990
Branch: Branch Immaterial - Warrant Officers, USA
Component: Selectees (Enlisted Men)
Source: Civil Life
Height: 68
Weight: 128