He attended Public School Number.
77, and Teachers College. He was President of the John P. Morrissey Electric Company Incorporated.
He entered politics as a Democrat. He was a delegate to the 1940 Democratic National Convention, and an alternate delegate to the 1944 Democratic National Convention.
Morrissey was elected on March 10, 1942, to the New York State Assembly, to fill the vacancy caused by the resignation of Robert F. Wagner, Junior.
He was re-elected three times and remained in the Assembly until 1948, sitting in the 163rd, 164th, 165th and 166th New York State Legislatures. In November 1948, he ran for Congress in the 18th District but was defeated by American Laborite Vito Marcantonio.
He died on October 29, 1966, at his home at 20 East End Avenue in Yorkville, Manhattan.
Morrissey was a member of the New York State Senate (22nd Doctorate) from 1957 to 1962, sitting in the 171st, 172nd and 173rd New York State Legislature.