The controversial midfielder was expected to leave Loftus Road during the transfer window with a move back to Marseille, the club where he spent last season on loan.
"I've been delighted with Joey, it's the first time I've worked with him and he couldn't have done more," Redknapp.
"He's been great on the training ground, great on the pitch on a Saturday and great off the pitch as well. He's a big part of the team at the moment.
"I'd never met him before and I thought he'd go to Marseille. My attitude was if he comes back, he comes back.
"He has come back and I've been impressed with him as a player and as a lad. I can only take him as I find him and he's not caused me a minute's problem.
"He talks about football, he loves the game, he trains well, he's good on the pitch and in the dressing room and I haven't seen a downside to him. I can't fault the way he's been."