 Kimanzi was appointed full-time manager of the Kenyan national side on 11 December 2008, having held the post as a caretaker since May 2008.He was sacked from the post of national team coach after the 2008 CECAFA Cup in January 2009 due to disputes between him and Kenyan football administrators.After a one-year spell coaching club side Sofapaka, he was reappointed as head coach of the Kenyan national team in November 2011.