Johnson has been sidelined for the last month after picking up a hamstring problem.
The former Crystal Palace and Everton man played for QPR's Elite Development Squad in the win over Brentford and he was happy with his return to action.
"I was delighted to be back out there," Johnson told the club's official website.
"I felt good, I felt sharp and it was a good run-out for me.
"It was important for me to get some minutes under my belt.
"I've been back in training for over a week now and I feel fine to be honest.
"I was only out for four weeks, it was only a minor hamstring injury, but it feels good to be back playing again."