President Uhuru Kenyatta has nominated Mr Charles Nyachae for judge of the East African Court of Justice (EACJ).
The former Constitutional Implementation Committee chairman is scheduled to take his oath of office in Uganda.
He will be sworn in at the East African Community presidential summit in Kampala, according to State House Spokesman Manoah Esipisu.
Mr Nyachae campaigned for President Kenyatta and his Jubilee Party in Gusii region during the August 8 General Election and October 26 repeat presidential election.
Jubilee had nominated him to the East African Legislative Assembly but he did not make it.
The EACJ is one of the organs of the East African Community (EAC) established under Article 9 of the Treaty for the Establishment of the EAC.
Its main purpose is to ensure adherence to law in the interpretation and application of and compliance with the Treaty.
Mr Nyachae, running on Jubilee ticket, lost the Kisii senatorial seat to Prof Sam Ongeri of ODM in the August poll, and his appointment may largely be seen as a reward by Jubilee.