The 31-year-old two-time Olympic champion timed 8min 06.01sec to take gold while compatriot Conseslus Kipruto took silver in 8:06.37 and France’s two-time Olympic silver medallist Mahiedine Mekhissi was third in 8:07.86.
“It’s good to be the king,” said Kemboi.
Kipruto was left devastated despite his second place at the age of just 18, saying: “I am so disappointed, I can’t even talk.”
Meanwhile, Mekhissi, who also won bronze two years ago, admitted that he was finding it hard to cope with the pressure.
“In the French team I am under a lot of stress and pressure, but I have to deal with it the best I can,” said the 28-year-old.
“I had to settle for bronze again but it is never easy to win one. I am on the podium and that’s what counts.”
Kemboi, also a three-time world silver medallist, had taken the lead at the bell, but dropped back entering the back straight after being elbowed by team-mate Kipruto, who also signalled something was up as he raised his arm angrily.
Mekhissi made his move at that moment cruising into second, but just as it seemed he might finally get the better of his close friend Kemboi he stumbled on landing after the third-from-last steeple.
Kemboi saw his chance and went wide to pass the Frenchman and then Kipruto rounding the final bend.
Kemboi, sporting a new Mohican style haircut, had a clear lead approaching the final obstacle and any hope Kipruto had of catching him ended as the 18-year-old made a mess of hurdling it.
It left his older team-mate to drift out wide on the track in his traditional style and cross the line pointing his finger derisively behind him.
Kemboi celebrated in his usual offbeat style, pulling up his team vest to reveal a message in Swahili written on a T-shirt and then dancing a jig in front of the photographers.
“Today it was good to have the same hairstyle as at the Olympics,” he said.
“I am wearing a t-shirt with a dedication to the President of Kenya (Uhuru Kenyatta) because I support him.”
He and Mekhissi – whose arms the Kenyan jumped into in a highly unusual celebration after winning Olympic gold last year – kept their post-race performance more muted although Kemboi went over and shook hands.
However, their close friendship shone at the medals ceremony.
Both simultaneously bit their gongs and, while Kipruto couldn’t wait to get away, the other two clowned around with Kemboi climbing not stepping on to the podium and continually pointing at his Mohican.
They both then climbed down with arms around each other’s waists grinning broadly, while Kipruto’s expression could best be described as stoney-faced.