On September 20, 1975, David Kotei (D. K. Poison) became the first Ghanaian Professional boxer to win a world crown. He turned professional under trainer Attuquaye Clottey. His first professional bout was on 5 February 1966 in Accra when he outpointed his opponent over six rounds. He became the national featherweight champion that year. Although he fought once in neighboring Togo in 1967, all his subsequent fights through to 1971 were all in Ghana. In 1972 however, he fought as much as seven times in Australia, winning five and losing two. He won the African featherweight title on 2 February 1974 when he knocked out Tahar Ben Hassen in the first round of a scheduled 15 round fight in Tunis, Tunisia. Later on 7 December 1974, he also won the Commonwealth featherweight title with a technical knockout over Evans Armstrong, a British boxer in round 10 of a scheduled 15 rounds bout. This victory gave him an opportunity to go for the World Boxing Council version of the world title. On 20 September 1975, in The Forum, Inglewood, California, United States, he beat Rubén Olivares by split points decision after 15 rounds to become the first Ghanaian world boxing champion. He relinquished the African and Commonwealth titles following this victory. The Ghana government gave him an estate house at Teshie-Nungua, an Accra suburb in honour of this achievements in boxing. He however lost the title in his third defense on 6 November 1976 by unanimous points decision to Danny "Little Red" Lopez in a fierce fight in Accra, Ghana. He is married with three daughters. He also defeated Fuku Yama in Japan.
DK Poison was never the same again after this defeat. He failed in 1978 to regain either the world or commonwealth featherweight titles. His last professional bout was in 1989 when he lost an African lightweight title fight. His professional record was 48 fights, W- 40, KO -24 and 1 draw.
According to reports and DK Poison’s own story, in 1976, he loaned an amount of US$45,000 to the Government of Ghana, then led by Ignatius Kutu Acheampong. The money was intended for the purchase of canned mackerel to mitigate the harsh economic and food conditions the country was facing. The loan had been facilitated by his management, which was led be Col John Slater. According to Kotei, the money was part of his reward for defending his title against Japan's Fuku Yama in 1976. The loan has not been paid back to date because shortly after the canned mackerels arrived in the country, the Acheampong's regime was overthrown by the Jerry John Rawlings.