John Turner Whalen was born in Maryland on June 18, 1898. His parents, Frank (b. 1850) and Priscilla J. ("Jennie") Fulton Whalen, lived in Howard County, Maryland, in the Mt. Hebron area. The Whalen family consisted of at least nine children, Mary (b. 1883), David "Fulton" (b. 1885), Frank, Jr. (b. 1888), Henry (b. 1891), Naomi (b. 1892), Rebekah (b. 1895), John Turner (b. 1898), and Robert (b. 1902).
In May 1917, at the age of nineteen, John enlisted in the Maryland National Guard in the 2nd Company Coast Artillery Corps. On August 7 of that same year, the company proceeded to Fort Howard, Maryland, during which time the entire National Guard in Federal service was drafted into the Army of the United States. During this time, Whalen spent much time in the hospital; he had a cast on his leg, most likely due to an attempt by the doctors to correct his flat feet. His foot continued to swell and to give him problems throughout his time at Fort Howard. On November 4, 1917, the 2nd Company, along with the 1st Company, was assigned the duty of guarding the piers at Canton and at Locust Point in Baltimore.
Not long after arriving at Locust Point, Whalen went to Walter Reed Hospital in Washington, D. C., for an operation to correct his flat feet. By January 1918, Whalen had returned to Locust Point. By that time, the companies had been rearranged, and Whalen was now part of the 6th Company, Coast Defenses of Baltimore. Relieved of guard duty in May 1918, the 6th Company returned to Fort Howard.
In July 1918, Whalen transferred to the 1st Anti-Aircraft Battalion. After a brief stint at Sparrows Point, Baltimore, he returned to Fort Howard in September 1918. A month later, he traveled to Fort Monroe, Virginia, for special training. This was a precursor to overseas service and the company was preparing to embark for France when the war ended on November 11, 1918. John T. Whalen received an honorable discharge on November 22, 1918.
After World War I, Whalen moved to Baltimore. According to the 1920 census, he lived with his parents; brothers, Henry and Robert; and sisters, Naomi and Rebekah; at 1502 Harlem Avenue, Baltimore, Maryland. The family hardware business, Carlin & Fulton Company, was located next door. According to the letters in the collection, the family regularly rented apartments in Baltimore City for the winter, while maintaining their house in Mt. Hebron, Howard County, Maryland. Whalen remained in Baltimore, working as a salesman for Daniel Miller Company until at least 1924.
Whalen married Jessamine Burroughs of Conway, South Carolina on April 26, 1924, and the couple settled in Wilson, North Carolina. They had one daughter, Ruth (b. ca. 1927). Whalen remained with Daniel Miller Company until the business liquidated in the 1950s, and he retired and moved with his wife to the Pamlico River. Following a stroke in his late seventies, Whalen and his wife moved to Charlotte, North Carolina, to be closer to their daughter, Ruth and her husband, Dr. Wharton Gaul. John Turner Whalen died on April 30, 1980, in Charlotte-Mecklenburg, North Carolina, at the age of eighty-one.