Police accused Feisal Mohamed Ali, from the coastal city of Mombasa, of being behind an international ivory poaching syndicate linked to a 3-tonne haul of elephant tusks seized in Mombasa in June 2014.
Poaching has surged in recent years across sub-Saharan Africa, where gangs kill elephants and rhinos to feed Asian demand for ivory and horns for use in folk medicines.
Kenya has imposed longer jail terms and bigger fines for wildlife poaching or trafficking, saying it is harming tourism, a major earner of foreign exchange.
Ali was arrested in Dar es Salaam in neighbouring Tanzania in December 2014 on a warrant issued by Interpol.
He faced two counts of handling ivory tusks and possessing ivory. He denied the charges but the court in Mombasa found him guilty on the second count and acquitted him on the first.
Magistrate Diana Mochache said: “120 elephants were killed and the value of the tusks was 44 million shillings.” She was referring to the consignment of elephant tusks confiscated during a police raid on a warehouse in Mombasa.
Four other suspects on trial alongside Ali were acquitted of all charges.
Ali’s lawyer Gerald Magolo told reporters his client would appeal the verdict. “There is no way he alone could be convicted,” Magolo said.
Prosecutors said they would appeal against the acquittal of the other four suspects.
“The guilty verdict is a strong message to all networks of poaching gangs, ivory smugglers, financiers, middlemen and shippers that Kenya will not watch as its elephant population is decimated or its territory used as a conduit for traffickers,” Kenya Wildlife Service said in a statement.
In January 2014, a Kenyan court convicted a Chinese man of smuggling ivory and ordered him to pay a fine of 20 million shillings or serve seven years in jail, the first sentencing since Kenya introduced its anti-poaching law.
In April, President Uhuru Kenyatta set fire to thousands of elephant tusks and rhino horns, destroying a stockpile that would have been worth a fortune to smugglers and sending a message that trade in the animal parts must be stopped.
In 2011, then-President Mwai Kibaki set fire to five tonnes of contraband ivory. His predecessor, Daniel Toroitich arap Moi, did the same in 1989.