Commings and Smith are the third and fourth members of the Georgia secondary to turn down the NFL draft this week.
"We came to Georgia of dreams and goals of winning championships," Commings said. "That's why I stayed."
With the news of Commings, the Bulldogs return nine starters from a defense that ranked fifth in 2011.
Smith, who has seen considerable playing time in his three seasons, is expected to slid into the starting role vacated by Brandon Boykin.
Outside linebacker Cornelius Washington will also remain in school instead of turning pro.
"I think this is a great group of guys," Washington said. "I've grown up a lot since I first got here. These guys are the reason I decided to stay. We had options and we chose to stay. That showed everybody in the room that we want to be something big next year."
Washington had five sacks and six tackles for loss in 2011.
In addition, sophomore signal caller Hutson Mason has decided against leaving the University of Georgia.
Mason considered transferring due to limited game action and being in the same class as starter Aaron Murray.
Mason was 18 of 30 for 254 yards and two touchdowns in 2011.