Jablonsky was born January 10, 1909, in Missouri, US, to mother Eugenia from England, and father Arthur from Germany. His parents did not have their own home; instead they lived along with Arthur's parents (Jablonsky's grandparents) in their Griesse Ave home in St. Louis County. Missouri. There they lived in a house of three generations. Jablonsky's grandfather August and mother-in-law Alice lived along with Jablonsky's parents Arthur & Eugenia, as well as Arthurs brothers, Jablonsky's uncles). Jablonsky's grandfather August immigrated from Germany in 1880 to the US, where he married his new wife Alice in St Louis, Missouri, in 1885. It is stated on the " Census: 1900, St. Louis, Missouri." that his parents were both born in the US, but it also states about his father Arthur that [It would appear Arthur was a son of August's by a prior marriage.] August's wife Alice was not Jablonsky's true grandmother. Furthermore, the information from the 1910 census shows that Jablonsky (1909) was in fact named after his uncle of the same name (his father's half-brother, who was called simply "Harvey Jablonsky" – minus the "J."), who is documented as living with the family on the 1900 census but not on the 1910 census. It is unclear exactly what happened to Uncle Harvey and why he was named after him.
In 1927 he attended Washington University in St. Louis. In 1929 he was made captain of his team and also awarded the highest honor for college football the College Football All-America Team award. After graduating Washington he enrolled in the United States Military Academy at West Point, New York, where he continued to play football in the position of guard, from 1931 to 1933, and became Army's captain in 1933. He graduated from the academy in 1934. Jablonsky remained at West Point as assistant coach for nine years. He was also married to his first wife Dorothy Jablonsky during these years, and the 1940 census shows he has had his first children, daughter Jean, born 1937 in Virginia, and son David Jablonsky, born 1939 in Panama.
On May 31, 1943, he was given the rank of lieutenant colonel and appointed executive officer of 515th Parachute Infantry Regiment "Jumping Wolves" at Fort Benning, Georgia. He remained an executive officer until November 1943, when the 515th PIR moved to Camp Mackall, North Carolina. On March 7, 1944, the "Jumping Wolves" became a part of the 13th Airborne Division at Camp Mackall. On January 18, 1945 the 515th PIR received orders to move to Camp Shank in New York. On January 25 the 13th Airborne Division received their overseas orders and embarked for Europe. They arrived at Le Havre, France, on February 8, 1945. On the same day, February 8, the men disembarked Le Havre, France, and boarded trains for Camp Lucky Strike near Ste Valery en Caux, France. A few days later the 515th former XO, Colonel Harvey J Jablonsky, (who had already been deployed to France) assumed command once again of the "Jumping Wolves".
On February 13, 1945, Jablonsky is listed as a commanding officer of the 515th PIR Although the unit did prepare for combat in Operation Comet (or Operation Market Garden) the strength of the Allied forces continually negated the need for airborne operations, and, as German defenses weakened, victory in Europe became a reality. The only combat action was left in the Pacific. Redeployment began on July 18, 1945, but by the time the 'Jumping Wolves' reached New York the war in the Pacific was over.
The 515th Parachute Infantry Regiment was deactivated at Fort Bragg, North Carolina on February 25, 1946. In 1946 he once again returned to West Point to serve as assistant coach.
Jablonsky is listed as a commander of the [187th Infantry Regiment (United States)] from July 1948 to June 1950. In February and March 1950 he participated in Exercise Swarmer, the largest peacetime airborne maneuvers ever conducted. The 187th airborne received the highest performance scores in this exercise, which was directly related to their being chosen to deploy to Korea as an airborne regimental combat team. ..credit for the superior performance of the Regiment must go to its commander at that time .. Harvey J. Jablonsky.
In September 1950 elements of the 187th were attached to the 1st Marine Division to participate in the amphibious landings at Inchon. Jablonsky served on the Joint Airborne Troop Board. Harvey commanded the 1st Armored Division at Fort Hood, Texas during 1963. Harvey also served in the Vietnam War.
Jablonsky was sent to Tehran, Iran during 1964–65, and he became chief military adviser from 1965 to 1968.
As chief military adviser he had the title Jablonsky, Major General Harvey J., USA, Chief, ARMISH/MAAG, Tehran, August 1965–July 1968 He was reportedly living on Price Rd. Olivette, St. Louis during 1967. Jablonsky retired from service in 1968 in Killeen, Texas, where he had previously served as the commanding general of the 1st Armored Division. He went on to become vice president of the Northrop Corporation, where he furthered his career within the private defense sector. He was sent back to Iran in 1970 by Northrop Corp. to work on an "advanced $225 million tele-communications system". He died of congestive heart failure on April 4, 1989, at the Nursing Center of the Army Residence in San Antonio, Texas. He was aged 80 and was survived by his children (and his late wife Virgie, who died on November 3, 2012). He is survived by his daughters Jean Rickard and Lea Uhre;, David Jablonsky (Col., USA, Ret.), Stepson Jim Tully. He also has numerous grandchildren and great grandchildren, three of whom have served in the army, and two also attended the US Military Academy.