John Joseph Sheehan was born June 11, 1902 in New London, Connecticut to John Joseph Sheehan (Sr.) and Julia Hayes. His siblings were: Joseph John Sheehan (b. 1899), Helen Josephine Sheehan (b. 1901), Julia Sheehan (b. 1903), Florence Sheehan (b. 1907), Mary Sheehan (b. 1909), and Thomas Francis Sheehan (b. 1911). John was married to Margaret Elizabeth Conroy on September 13, 1920. They had one daughter, Gloria (b. March 1926), who is still living.

His Navy record indicates he was 5'7" and 128 pounds with light brown hair, blue eyes, and a ruddy complexion when he enlisted on July 1, 1921. He listed his birth date as June 11, 1900. He was assigned to the Submarine USS 0-7 until 1925 when he reenlisted in July for 4 more years and was transferred to the S-51. He rose to the rate of Motor Machinist Mate first class and had good evaluations for his technical ability throughout his career. He earned a 4.0 for sobriety and obedience at all times.

According to the New York Times newspaper (July 10th and 11th, 1926), Sheehan's body was not recovered until the S-51 was brought to dry dock at the New York Navy Yard. His body was one of eighteen victims recovered from the hull and taken to the morgue of the Navy Hospital four blocks away on Flushin Avenue. Sheehan's address was listed as 125 Thames Street, Groton, CT at the time the newspaper article was written. He was buried in St. Mary's Cemetery in New London, CT in July or August of 1926.

Biography written and submitted by Katie Gallemore, great-granddaughter of Sheehan.