During his time on the bench, Mr. Johnson presided over thousands of civil and felony criminal cases and gained tremendous experience and insight in handling class-action cases, real estate and restrictive covenant matters, health care fraud and complex business and tax litigation cases. Several noteworthy cases presided by Mr. Johnson both as a judge and practicing attorney are: Thurbert Baker v. Metropolitan Atlanta Chamber of Commerce, Inc., et. al., relating to revealing the bid proposals for the 2009 NASCAR Hall of Fame and the 2009 Super Bowl; The State of Georgia v. Arthur Tesler, which involved the murder of Kathryn Johnston; and Southern Center for Human Rights v. The Georgia Department of Corrections (GDOC), which concerned an action seeking to enjoin the execution of a defendant convicted of a capital offense. Mr. Johnson has also successfully argued before the Supreme Court of Georgia in the matter of Fantasia v. The State, 268 Ga. 512 (1997), which revolved around the issue of self-incrimination.

Additionally, Mr. Johnson has represented individuals, small and medium-sized businesses and Fortune 500 corporations. Specifically, he has focused on representing commercial clients in multiple areas, including airport vending compliance and contracts, business disputes in diverse areas and licensing issues. Moreover, Mr. Johnson has a wide-ranging government relations practice, having represented clients before federal, state and local agencies, as well as clients involved in state and federal investigations.