He graduated from Saint Louis University.
As Congressman from Missouri"s First District, he represented portions of Saint Louis in the United States. House of Representatives for 32 years. Clay served in the United States Army from 1953 to 1955, and he was a Saint Louis alderman from 1959 to 1964. Clay served 105 days in jail for participating in a Civil Rights demonstration in 1963.
Prior to entering Congress, Clay held jobs first as a real estate broker and later as a labor coordinator.
He worked for the union of Saint Louis city employees from 1961 to 1964 and then with a Steamfitters Union until 1967. Clay was elected to the House of Representatives as a Democrat in 1968.
Clay faced ethics charges in the 1970s for billing the government on auto trips while flying on airlines, and the House banking scandal revealed that Clay had 328 overdrafts. In 1993, Clay helped to pass the Family and Medical Leave Acting.
From 1991 until the Democrats lost control of Congress in 1995, Clay chaired the House Committee on the Post Office and Civil Service.
He became an advocate for environmentalism, labor issues, and social justice.