(Henrietta) May Steinmesch was born on May 9, 1893, to parents Henry Steinmesch and Adelaide Caldwell, in St. Louis, Missouri. She received a B.S. in Architecture from the University of Washington in St. Louis in 1916. Following her graduation, she worked for the St. Louis City Planning Commission until 1923 as a draftsperson, designer, and delineator. Throughout the 1920s and 1930s she strung together several jobs, teaching drafting and interior design courses, working for St. Louis firms, and building a small business around private interior design commissions and consultations.

During World War II, Steinmesch worked for the U.S. Army of Engineers and Air Force; her work included plotting airfields and teaching drafting and map-making skills to naval officers. After requesting to be discharged in 1943, she went to work for the Western division of the United Services Organization, where she stayed until 1946, after which, she worked for various firms and agencies in California until her retirement in 1958.

In 1915, while Steinmesch was still at the University of Washington she founded an undergraduate organization for women studying architecture called "La Confrerie Alongive." Later, Steinmesch, along with the other women studying at UW, organized with women in programs at the Universities of Minnesota, Texas, and California. In 1922, the four chapters formed a national organization called Alpha Alpha Gamma, for which Steinmesch served as president from 1928 to 1930. Alpha Alpha Gamma eventually became the Association for Women in Architecture (AWA) in 1948. Although AWA later dissolved as a national organization, its California chapter remains active as a professional organization, now called the Association for Women in Architecture and Design, or AWA+D.

H. May Steinmesch passed away on May 21, 1979.