The 22-year old Northern Ireland will spend the upcoming season on loan at St Andrew's, following a successful spell there last campaign, and is excited about receiving regular game time under Lee Clark.
"I am really looking forward to it," Ferguson said.
"I had a meeting with the (Newcastle) manager and he said he wanted me to get out and have a full season of games.
"I am really happy it has happened like this.
"It's good for me to get experience and come back to Birmingham.
"I just want to play as many games as I can and help the team as much as I can.
"I came for the last two months and that makes it a lot easier this time. I know all the lads and staff here.
"And the loan being over a season, that's good for me - and hopefully Birmingham, too."