McGary, who was selected with the 31st overall pick of the first round, matched up against veteran defensive end Datone Jones, a former first-round pick of the Green Bay Packers, to start the game.
“We knew we were only going to give him a half,” Quinn said. “He was definitely one champing at the bit to go in the second half, but we said no. We’re going to stick to the plan. For him, he really showed his physicality.”
On the first series, McGary pushed Jones outside on second down, and on third down he held up as Jones twisted inside on a stunt.
On the third down of the second offensive series, McGary did a good job pushing linebacker Leon Jacobs away from the quarterback on a solid block.
McGary, the second of the Falcons’ first-round draft picks, returned to full practice Sunday. He had not played a snap in the exhibition season until this game.
Before the procedure, McGary was receiving about 50 percent of the snaps with the first-team offense at right tackle. He was competing with Ty Sambrailo for the starting spot.
Now, the big question is whether the Falcons saw enough to start McGary over Sambrailo, who has a shoulder injury.
The Falcons open the regular season against the Minnesota Vikings at 1 p.m. Sept. 8 in Minneapolis.
With McGary and his offensive line mates holding up, backup quarterback Danny Etling guided the Falcons to three touchdown drives and a 21-3 lead.
Struggling kicker Giorgio Tavecchio missed a 53-yard field goal with 24 seconds left in the first half.
Jacksonville added a field goal for the 21-6 halftime margin.
In the third quarter, Blair Walsh made a 46-yard field goal to give the Falcons at 24-6 lead.