The bankers beat Talanta FC 2 - 0 in NSL match played at Camp Toyoyo, to secure a direct ticket to the Kenya top-flight league.
After a scoreless first half, KCB needed the inspiration of Dennis Gicheru and Evans Abuka's goals on 81st and 90th minutes respectively to romp to victory and make a return to the SportPesa Premier league after 3 years stint in the second tier.
The bankers have accrued 75 points, 7 points clear of Nairobi Stima and now joins the already promoted Western Stima to the top flight league.
"I am elated to see the team return back to KPL, having been relegated while I was a player, it was painful, but today is a different story as we celebrate. I salute all the players for their commitment and the management support," said the delighted, former player and interim coach Elvis Ayany
Meanwhile, Nairobi Stima drew 1 - 1 against Administration Police as Ushuru won 3 - 0 against Nakuru All-Stars to throw the race for the third position down to the wire, as both teams are now tied with 68 points, though Nairobi Stima has superior goal difference.
SPL promotion/relegation play-off
Vihiga United beat Nakumatt FC 2 - 0 to condemn them to the relegation play-off. Nakumatt lies third in the bottom log.
Golden boot winner
Elsewhere, Kariobangi Sharks' Eric Kapaito walked home with the golden boot after scoring in a 1 - 1 tie against Chemelil Sugar, at Camp Toyoyo to take his tally to 16 goals.
Gor's Jacques Tusiyenge blasted his chance to oust Kapaito after his side lost 1 - 0 to Tusker fc at Thika Municipal Stadium.