Kelly graduated from Samford University in 1984. He began his career as director of public relations for the Metropolitan Development Board from 1987 to 1993. After that he worked as a reporter and city editor for the weekly Black & White. In 1999 he accepted an appointment to Mayor Bernard Kincaid's staff as senior adviser and director of the Office of Public Information. In that position he helped coordinate public involvement in the creation of the Birmingham Area Technology Leadership Alliance to nurture the development of high-tech industries in Birmingham.
In 2003 Kelly left City Hall to work as a public relations consultant and freelance writer. He authored a multi-part biographical series on former Mayor Richard Arrington for Birmingham Weekly in 2005. In 2006 he managed Patricia Todd's campaign for Alabama House of Representatives District 54. He co-founded Weld for Birmingham with Kyle Whitmire, Glenny Brock and Heather Milam in 2011. Brock stepped down in the Spring of 2012. Whitmire's departure for the Alabama Media Group that Summer prompted Kelly to publish a bitter farewell.
- Kelly, Mark (2008) A Powerful Presence: The Birmingham Regional Chamber of Commerce and the History of Birmingham. Birmingham"
- Kwon, Wade (July 31, 2012) "Whitmire departs Weld, leading to online acrimony from the publisher" Media of Birmingham