Of Japanese descent, Kono was born in Sacramento, California, on June 27, 1930. Kono’s family was relocated to Tule Lake internment camp in 1942 during World War II. Sickly as a child, the desert air helped Kono’s asthma. It was during the relocation that Kono was introduced to weightlifting by neighbors including the late Noboru “Dave” Shimoda, a member of the Tule Lake weightlifting and bodybuilding club and brother of actor Yuki Shimoda and his friends, Gotoh, Toda, and Bob Nakanishi. After 3½ years they were released and Kono finished high school at Sacramento High. He later worked for the California Department of Motor Vehicles and attended Sacramento Junior College.

Kono was drafted into the U.S. Army in 1950 but was kept home from the Korean War after officials learned of his Olympic potential.

Kono was also a successful bodybuilder, winning the Fédération Internationale Haltérophile et Culturiste Mr. Universe titles in 1954, 1955, 1957 and 1961. After his retirement he turned to coaching, taking on the Mexican 1968 Summer Olympics and West German 1972 Summer Olympics weightlifting teams before becoming head coach of the United States’ Olympic weightlifting team at the 1976 Summer Olympics.

Kono was a gold medalist at both the 1952 Summer Olympics and 1956 Summer Olympics, and a silver medalist at the 1960 Summer Olympics under coach Bob Hoffman. Kono won the World Weightlifting Championships six consecutive times from 1953 to 1959 and was a three-time Pan American Games champion; in 1955, 1959, and 1963. A knee injury prevented him from qualifying for the 1964 Summer Olympics in Tokyo and the following year he retired from the sport. He set a total of 26 world records and 7 Olympic records, making him the most accomplished U.S. male weightlifter to date.

Along with his weightlifting and bodybuilding titles, Kono was an eight-time Amateur Athletic Union James E. Sullivan Award finalist, an award given annually to the top American amateur athlete. He was also one of the first members of the Hawaii Sports Hall of Fame in 1978. In 1990, Kono received the Association of Oldetime Barbell and Strongmen Highest Achievement Award and was inducted into the United States Olympic Hall of Fame. He was elected to the International Weightlifting Federation Hall of Fame in 1993. In 2005, the International Weightlifting Federation named Kono the “Lifter of the Century.”

Kono appeared in Universal Newsreel volume 32, number 63, August 6 1959. Kono is depicted as part of a mural located at 37 West Philadelphia Street in York, Pennsylvania. This mural was finished in 2000.

Kono died on April 24, 2016 in Honolulu, Hawaii from complications of liver disease, aged 85.