After receiving his doctorate of Juris Prudence from the University of Tennessee at Knoxville, Councilman Brown became president and CEO of the Knoxville Area Urban League. He served in this capacity from 1987 through 1992. During his tenure as president and CEO of the Knoxville Area Urban League, Councilman Brown established the Knoxville Area Urban League Computer Training Center, and the Promoting Learning Through Utilizing Scholarships with Pellissippi State Technical Community College.

In 1993 Councilman Brown began his law practice with the law firm of Campbell & Dawson. December of 2005 Mark co founded the firm Clark, Brown & Waters an association of attorneys. He has served as a special judge to the Knox County General Sessions Courts. He is a former Chairman of the Knox County Election Commission and member of the Spirit of Peace music Ministry. In 1990 Councilman Brown was named by Ebony magazine as one of the leaders of the future for the age group 30 and under. He has participated in voter registration drives and neighborhood clean-ups.

In 1998 councilman Brown served as Vice Chair of the Bernstein Commission on Police (which proposed the Police Advisory Review Commission). Throughout Councilman Brown's life he has been involved in several civic organizations, commissions and received various appointments, designations and awards. What is most important to Councilman Brown is that we all realize that "There is more that unites us than divides us".