Brennan attended Mississippi State University and received a B.B.A. in 2004. After receiving his undergraduate degree, Brennan attended Mississippi College School of Law where he received his J.D. in 2006.

Brennan joined Chapman, Lewis, & Swan as an associate in March of 2007. His primary areas of practice are General Civil Litigation, Personal Injury, Products Liability, Medical Malpractice, Nursing Home Abuse, and Premises Liability.

Brennan is admitted to practice before all State Courts in Mississippi, the U.S. Court of Appeals for the 5th Circuit, and the U.S. District Courts for the Northern and Southern District of Mississippi. Brennan is also admitted to practice before all State Courts in Tennessee.

Brennan is a member of the Coahoma County Bar Association, the Mississippi Bar Association, the Mississippi Association for Justice, the American Bar Assocation.

Brennan is married to a Clarksdale native.