Johnson regained the ranking after finishing third, one shot ahead of Rose, at Atlanta's East Lake Golf Course.
Rose however was more than satisfied with his week's work, which earned him a $10 million FedEx Cup winner's cheque.
"There were a lot of scenarios at play this week and that's what the beauty of this format is," Rose said. "I think obviously for me this year it rewarded consistent golf."
"For me, I was trying to do my best to win this golf tournament and scoop the double jackpot.
"But far and away, being next to this trophy is something I'm very, very proud of, and it was -definitely with five, six holes to play, it was pretty precarious.
"I was in a great position around the turn, and then things just got tricky out there."