The 30-year-old has had a turbulent time at the Millers since joining as Steve Evans' marquee signing in the summer, having been stripped of the captaincy, dropped from the side, falling out with coach Eric Black and not featuring at all under new boss Neil Redfearn.
He sealed a last-minute move to Sky Bet Championship rivals Birmingham on Thursday before the loan window shut - initially for a month - and is hoping to get some minutes under his belt at St Andrew's, having not pulled on his boots since September 15.
"I'm delighted, it's a club with great history and a club that is going places especially with the manager," he said of the move.
"It's been good. First day was Friday so it was a bit low key, building up for the game against Brighton on Saturday. Obviously I didn't travel so I trained with the 21s on Saturday which was good.
"I'm hoping for minutes, as many games as possible, I haven't played all that much this season so I am looking to play as many games as possible and see what happens after January 2."
Asked whether his time at Rotherham had been frustrating Halford replied" "You could say that! It has been very strange."
Halford's versatility was a big selling point when he arrived at New York Stadium in July and in his short time in the side he played right-back, centre-back and as a striker.
He is happy to fill in where necessary for Gary Rowett's side but knows he needs to become a master of one position rather than a Jack of all.
"It's not an overly big squad so he is looking for me to be as versatile as I can and cover as many positions as I can," he added.
"I'd eventually like to settle down in one position towards the end of my career but I am here to help and try and get as many minutes as I can."
