Born in Ogden on 26 March 1906, Morris Blaine Peterson received his early schooling in the public schools of Ogden and at Weber College. He graduated from the University of Utah in 1931 and from Georgetown Law School in 1938. For a time he was law clerk to Justice Eugene E. Pratt of the Utah Supreme Court before engaging in the private practice of law in 1941.

Peterson served in the state legislature from 1955 to 1957, and was also Weber County attorney. Elected as a Democrat to the United States House of Representatives, he served from 1960 to 1962. He failed to win reelection in 1962.

Following his return to Utah, he became a member of the Great Salt Lake Authority from 1968 to 1969. He served as chairman of the Weber County Tax Payers Association, and he was a special consultant to the director of the Food for Peace Program in 1963. He remained a resident of Ogden until his death there on 15 July 1985. He is buried in the Ogden City Cemetery.