|Reference style||The Most Reverend|
|Spoken style||Your Excellency|
On March 7, 1957, Amissah was appointed Auxiliary Bishop of Cape Coast and Titular Bishop of Bencenna, receiving his episcopal consecration on the following June 16 from Archbishop William Thomas Porter, SMA. Amissah replaced Porter as Archbishop of Cape Coast on December 19, 1959.
During the late 1950s, he also studied the native and controversial custom of pouring libations on important occasions. Amissah explained that before Church leaders determine if this practice is good or bad, they must understand what villagers intend when they pour a libation.