The deal was worth 27 million US dollars, which was made to increase its presence in east Africa's top economy.
The 300 million rand deal gives South Africa's third-largest life insurer access to Cannon's short-term insurance and asset management products.
MMI Holdings operates in 12 countries outside of South Africa including Botswana, Ghana and Nigeria. It already has a presence in Kenya through its Metropolitan Kenya unit.
South African companies are increasingly looking to buy up firms on the fast-growing continent to offset slower expansion at home.
Shares of MMI fell 0.6 percent to 22.56 rand at 1255GMT.