Champion Jethard Cidevant took the prestigious title at the NEC Birmingham on Monday night.
The two-year-old dog, known as Cid, from Colchester, Essex, won the hound category and beat six other dogs in the final.
Owner Paul Singleton, who has been breeding dogs for 30 years, said winning was a dream come true after entering the show since the early 1970s.
"It's a wonderful achievement. I still can't believe I have won, I never expected to win but I thought I could do well," he said.
"I hope that all the people who have a Basenji are proud of the fact that Cid managed to take best in show."
Praising his dog, he added: "He's a wonderful dog, he won his first championship when he was just seven-and-a-half months old. It's a wonderful breed of dog.
"He's sweet, but he has a lot of sparkle and he's difficult to control in the ring, but that is what I like."
'Blueprint'
The Best in Show judge, Mrs Ann Arch, said: "Cid was a deserving winner.
"Every breed has a blueprint that you judge when selecting the top winner. This dog fitted that blueprint beautifully. He was sound, unexaggerated, he is a very, very nice dog."
A Pembroke Welsh corgi called Penliath Shooting Star was runner-up. A pointer, Siberian husky, toy poodle, Pekingese and a terrier also made the final line-up.
The dog show opened on Friday, after being postponed for more than two months because of the foot-and-mouth epidemic.
The event is usually held in March, but with the disease at its peak organisers decided to postpone it amid fears that pet owners may inadvertently spread the virus.
More than 20,000 top pedigree dogs competed this year and due to the relaxation of quarantine laws, dogs from abroad were allowed to compete for the first time in its 110-year history.