Founded in 1965 as the Tri-College Council, CMSS was created to provide an independent forum for the discussion by medical specialists of issues of national interest and mutual concern. Founding members were the American College of Obstetricians and Gynecologists, the American College of Physicians, and the American College of Surgeons. In 1967, as other specialty societies joined, CMSS adopted its current name. Today, 43 societies with more than 790,000 U.S. physician members are members of CMSS.

CMSS is a 501(c)(3) not-for-profit association incorporated in the state of Illinois. 

It is governed by its assembly, the Council, which consists of one or more representatives named by each member society. The assembly meets twice yearly, usually in May and November, for a period of one and one-half to two days. Only physician representatives may vote in Council and serve as Officers on the Board of Directors. 

The business affairs of CMSS are managed in the interim between regular meetings by a eight-person elected Board of Directors. Headed by a President, other Officers are the President-Elect, Secretary, Treasurer, Past President, Public Board member, and Executive Vice President. Officers are elected to two-year terms. 

CMSS is supported principally by annual dues contributed by its members.