Confirming the development, Nzoia Sugar's chairman Yappets Mokua said they reached the deal with their Kenyan Premier League (KPL) rivals and finally let the forward join the former Sportpesa Shield Cup champions.
The value the transfer of the player has not been made public yet.
"After a long negotiation with Kariobangi Sharks, we have finally let Otieno leave because Sharks met our asking price for him" Mokua told Goal.
"We hope to sign his replacement from the lower leagues or maybe from the neighbouring schools. We attended the school games and we have identified a number of young players whom we think can fill the void."
Otieno scored four goals for the Bungoma-based side in the 2018/19 season after he was roped in from Bukembe High School.
At his new club, Otieno will battle for a starting berth with James Mazembe and Erick Kapaito in the striking department.
Kariobangi Sharks will host the English Premier League side Everton on July 7 for the SportPesa Cup encounter, which is the first opportunity for Otieno to make his debut.
Since Elvis Rupia's move to Zambia's Power Dynamos in 2018, Sugar have struggled to sign a prolific striker, but Mokua is optimistic that they will soon land a forward of Rupia's calibre.
"Rupia was our best player and we hope sooner rather than later we will be able to find another striker that will give us goals like Rupia did. You know as a club, we have to sell and sometimes we sell our best players," Mokua added.