Cannon was among the first missionaries of the LDS Church to preach to black people in West Africa (specifically in Nigeria and Ghana) and was part of the first group of missionaries sent to establish official congregations of the church in West Africa.

After graduating, he managed a Cannon family business, the Salt Lake Stamp Company.

In 1948, Cannon was elected as a Republican member of the Utah House of Representatives for Salt Lake County.

In 1978, the LDS Church announced a revelation ending the previous restrictions on black people receiving the priesthood or participating in temple ordinances.

They—along with Rendell and Rachel Mabey—preached in Nigeria and Ghana, baptized hundreds of converts, and established 35 branches and 5 districts of the church.

In the late 1980s, Cannon and his wife were the directors of the church's visitors' center in Nauvoo, Illinois.