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.
[6] He however lost the title in his third defence 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.
[6] According to reports and Kotey's own story, in 1976, he loaned an amount of 45,000 dollars to the Government of Ghana, then led by Ignatius Kutu Acheampong.
[9] The money was intended for the purchase of canned mackerel to mitigate the harsh economic and food conditions the country was facing.
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 General Akuffo in a military palace coup in October 1975.
[12][13] After Kotey won the World featherweight title in Accra in September 1975, one of Ghana's leading highlife artists at the time, Senior Eddie Donkor released a song in Twi in his honour entitled "D. K. Poison Mo".