Jack Dempsey (1895-1983) was an American boxer.

Jack Dempsey was born June 24, 1895 in Manassa, Colorado. His family were members of the Church of Jesus Christ of Latter-day Saints and Jack was baptized when he turned eight years old. Due to his families poor financial situation he dropped out of grade school to work and left home at sixteen to find a job. He began boxing in saloons and soon became a professional boxer. On July 4, 1919 he fought current heavyweight champion Jess Williard. He would defend his title until September of 1926, when he lost to Gene Tunney. He failed to win the rematch with Tunney the following year in the famous "Long Count" fight. He retired from professional boxing, but continued to be involved with exhibitions and announcing.

He married actress Estelle Taylor in 1925. They were divorced in 1933, and Dempsey married Broadway singer Hannah Williams. They later divorced as well and Dempsey remarried shortly after to Deanna Piatelli in 1943. They were married until his death in 1983.

During World War II Dempsey joined the Coast Guard reserve and was assigned in June 1942 at Coast Guard Training Station in New York, where he was assigned as "Director of Physical Education." Dempsey also made many personal appearances at fights, camps, hospitals and War Bond drives. Dempsey was promoted to lieutenant commander in December 1942 and commander in March 1944. Dempsey was released from active duty in September 1945 and he was given an honorable discharge from the Coast Guard Reserve in 1952.

In 1935 Dempsey opened 'Jack Dempsey's Broadway Restaurant' that he would manage until 1974. He also wrote several books including an autobiography called 'Dempsey' that he authored with his daughter and 'Championship Fighting: Explosive Punching and Aggresive Defence'.

He died May 31, 1983 in New York City, New York.