Milton Kinsey was born on December 3, 1896. He was educated at Wisconsin University and Washington University Schools of Engineering. Kinsey was a member of the U.S. Army Corps of Engineers, becoming a lieutenant of engineers before leaving after 3 years of service. Between 1920 and 1924, Kinsey worked for the St. Louis-San Francisco Railroad. He was also employed as an Assistant Engineer with the United Railways Company of St. Louis during the same years. In 1935, Kinsey joined C.E. Smith and Co., Consulting Engineers, first as an Assistant Engineer and later as a partner.  As a part of this company, Kinsey provided consultation with various utility cases before public commissions, representing the City of St. Louis, municipalities, small companies, and railroads. In 1936, Kinsey formed a partnership with Robert M. Boyles, and from 1936 to 1941, Boyles and Kinsey, Consulting Engineers represented the City of St. Louis and other municipalities in public utility rate and valuation matters. Kinsey became Chief Engineer of the Missouri Public Service Commission in 1941, and in this position he had general administrative and supervisory charge of the Engineering Department and was responsible for the determination of policies and planning of departmental activities regarding the inventory, appraisal and valuation of all privately owned public utilities in Missouri.

During World War II, Kinsey was commissioned as Captain, Allied Military Government, and after the war he accepted the position of Director of Public Utilities for the City of St. Louis.  With this job, he was in charge of the operation and maintenance of the city water department, street lighting system, municipal bridge, city-owned power plants, and the municipal airport.  From 1944 to 1949, Kinsey served as President of the Board of Public Service of the City of St. Louis before returning to private consulting, forming with H.C. Brockhoff the firm of Kinsey and Brockhoff, Consulting Engineers. Kinsey died in 1980.