The Kim Sisters, formed in 1953, were "the first South Korean music group to achieve success in the U.S." according to Wikipedia.
Sue and Aija's parents were Kim Hae-song, a popular conductor, and Lee Nan-young, one of Korea's most famous singers before the Korean War, best known for her song, "Tears of Mokpo." Mia was Sue and Aija's biological cousin whose father was Lee Bong-ryong, a musician and Lee Nan-young's elder brother; she was later adopted by Lee Nan-young.
In 1950, North Korea captured and later executed Kim Hae-song, the father of Sue and Aija. The Kim Sisters were formed in 1953. Following her husband's kidnapping, Lee Nan-young adopted Mia and had her daughters form a singing group in order to support the family. Lee bought American records on the black market so that the girls could learn songs like Hoagy Carmichael's "Ole Buttermilk Sky," which they performed in bars and nightclubs for American soldiers stationed in South Korea during the Korean War.
The Kim Sisters were popular among the American troops, who spread the word about the group to American entertainment producer Tom Ball. He flew to South Korea in 1958 to hear the group perform, and The Kim Sisters signed a contract with Ball soon after.
Sue, Aija, and Mia Kim appeared on The Ed Sullivan Show 22 times.
Here, the K-pop pioneers perform "All Shook Up," originally recorded by Elvis Presley in 1957:
Previously:
• Korean pop music before 'K-pop': three six-hour mixes of 70s and 80s hits
• South Korea blasts K-pop at North to piss off Kim Jong Un
• Dear Leader Kim Jong Un declares K-Pop a 'vicious cancer'
• Scientists use DNA Typewriter to encode K-pop lyrics into human genomes
• Watch North Korean officials' reactions to hearing K-Pop for the first time