Mitchell was born in St. Paul, Minnesota, December 14, 1939. The son of Clarence M. Mitchell Jr. and Juanita Jackson Mitchell, he attended Baltimore City public schools and then Gonzaga High School in Washington, D.C.. After high school, Mitchell attended the University of Maryland and Morgan State University. He is a member of Kappa Alpha Psi fraternity.
Mitchell first served in the Maryland House of Delegates, Legislative District 4 (Baltimore City) from 1963 to 1967; he was elected at 22 and sworn in at 23 years old.
After 4 years in the House, he ran for the Maryland Senate and won. During the next 20 years he represented Senate, Legislative Districts 10, 38 & 39, all in Baltimore City. 1967-86. During that time he was the Deputy majority leader, 1975–78, Majority whip, 1979, member of the Judicial Proceedings Committee, Co-chair of the Joint Committee on Federal Relations and Chairman of the Executive Nominations Committee.
On the national level, Mitchell was also elected to serve as President of the National Black Caucus of State Legislators, from 1979 to 1985.
Mitchell pleaded no contest in 1964 to charges of failing to file income taxes.
In 1983 he was charged with carrying a weapon onto an airplane.
A year after leaving the Senate in 1986, Mitchell was convicted of attempting to obstruct a grand jury, committing wire fraud and attempting to tamper with a federal investigation in the Wedtech scandal. He was sentenced to 54 months in prison, but was released after serving 18 months.
Mitchell was married to Joyce Ellis. Their seven children include Clarence Mitchell IV, who served in the Maryland House of Delegates and the Maryland State Senate, and also hosted The C4 Show on WBAL radio.
Mitchell died October 11, 2012, in Randallstown, Maryland.
- Lambert, Jack (October 11, 2012). “Clarence M. Mitchell III, former Md. state senator, dies”. Baltimore Business Journal. Archived from the original on October 14, 2012. Retrieved July 20, 2019.
- “Clarence M. Mitchell III, MSA SC 3520-2731”. Archives of Maryland (Biographical Series). Maryland State Archives. October 11, 2012. Retrieved October 26, 2012.
- Rector, Kevin (October 21, 2012). “Mitchell remembered as pioneer, fighter for justice”. The Baltimore Sun.
- Barone, Michael; Ujifusa, Grant (October 1987). The Almanac of American Politics 1988. National Journal. p. 534. ISBN 978-0892340378.
- Wenger, Yvonne; Kelly, Jacques (October 11, 2012). “Former Md. Sen. Clarence Mitchell III has died”. The Baltimore Sun. Retrieved July 20, 2019.
- “2 are sentenced in Wedtech case”. The New York Times. Associated Press. February 6, 1988.