Catherine May was born Catherine Dean Barnes at Yakima, Washington, in 1914. Graduating from Yakima High School in 1932, she attended Yakima Valley Junior College through 1934, and then received the Bachelor of Science degree in 1936 and the Fifth Year Education Certificate from the University of Washington in 1937. From 1937 through 1940, she taught English in the Chehalis High School, interrupting this tenure for a brief period in 1939 to study speech at the University of Southern California.

At the close of the school year in 1940, Mrs. May entered into a career in radio journalism and advertising, first with station KMO in Tacoma, and later stations KOMO and KJR in Seattle. From 1942 to 1944, she worked in advertising for Strange and Prosser Advertising Agency and the Federal Insurance Company, both of Seattle. She was in New York City 1944-1946 in the employment of the National Broadcasting Company. Following this, Mrs. May returned to Washington State, continuing in radio journalism at station KIT in Yakima through 1957.

Catherine May entered politics actively when she was a candidate and elected to the Washington State House of Representatives in 1952, representing a Yakima district. Re-elected twice, she remained a member of the state legislature until 1958, when she secured the Republican nomination to succeed retiring Republican Congressman, Otis Halbert Holmes. She was elected to the United States Congress six times and served until 1970 when she was succeeded by Democrat, Mike McCormack. Upon leaving Congress, she was appointed one of the Federal government trustees of the quasi-public National Railroad Passenger Corporation (AMTRAK). In May of 1971, President Richard Nixon appointed her a member and Chairman of United States Tariff Commission.

When Catherine May entered the United States Congress in early 1959, she was the first woman Representative from the State of Washington. Also, she was the first Representative from the State of Washington in quite a few years to be appointed to the Committee on Agriculture, an assignment that is highly desired by Representatives from Washington State. Mrs. May held this Agriculture Committee assignment during her entire tenure in Congress. Work in this committee, and her efforts on behalf of her constituents, occupied the center of attention throughout her congressional career. Partially due to this concern with agricultural policy, May was selected as a Congressional member of the National Commission on Food Marketing, one of the numerous "study commissions" of the 1960’s. During her last term in office, she received a second committee assignment, the Joint committee on Atomic Energy. She was, lastly, a member of the somewhat ephemeral but nevertheless interesting, House Beauty Parlor Committee.

Although Representative May’s attention centered on her committee and constituent work, her career was not dominated by either of these. Like most members of Congress in the 1960’s, she was involved in almost every major public issue of the time. Her papers reveal significant interests in consumer affairs, the "hunger" and poverty issues, transportation policy, drugs, minority relations, and, on occasion, foreign affairs. The return of a Republican administration to power in the 1968 election increased May’s contact and concern with the whole range of governmental and public affairs. She was one of the congressional leaders that supported the administration. She was apparently considered for the post of Secretary of Agriculture at the time the Nixon Administration was organized. After leaving Congress, she continued to receive significant appointments, including United States Tariff Commissioner, a position of importance to the economic issues of the early 1970’s.