It has been a roller-coaster week for the 19-year-old forward since he struck his first goal for the Ibrox men after coming on as a second-half substitute against Dunfermline on Saturday.
He was rewarded for that strike with his first senior start as a Rangers player against Albion Rovers in Monday night’s William Hill Scottish Cup quarter-final replay.
The former East Stirlingshire loanee made the most of his opportunity as he swept in the cross that set-up Fraser Aird’s opening goal in the 2-0 win.
Gallagher’s impressive impact has already made him a favourite with the Light Blues faithful, but it has all come as a shock to the teenager.
He said: “To get my first goal and then first start was unbelievable. The confidence the manager has shown in me has been amazing.
“I was a bag of nerves five minutes before the game on Monday but I loved every minute of it. Hopefully there’s more to come.
“The support I’ve had since then was great. My phone hasn’t stopped ringing and I’ve been sent lots of nice, encouraging messages and tweets.
“I’ve even been recognised out in the street, which was a bit of a weird one. Someone came up to me and asked if I was Calum and said ‘well done’.
“I told my mum and she couldn’t believe it. She thought I was lying.
“I don’t know if I’m famous yet but this sort of thing is what people dream about from a young age, so it’s a real blessing.”
The turnaround for Gallagher is even more impressive considering he was almost shown the door by the new League One champions.
“When I was in my last year of being part-time, I was told that the club was not sure if they wanted to keep me on or not,” he said.
“I’d even ended up playing in the exit trials and I was looking for teams to move to.
“But we then had the Glasgow Cup final against Celtic, where I came on for the last 20 minutes and did really well and got asked to stay on. That was the turning point for me.
“So everything this week has been a massive turnaround that I just didn’t see coming.”
Gallagher should feature in Sunday’s clash with Brechin at Glebe Park but the youngster has already got one eye on next month’s Scottish Cup semi-final with Dundee United.
Best friend and former class-mate from St Ninian’s High in Giffnock Andy Robertson has impressed so much since moving to Tannadice from Queen’s Park in the summer that he has already been handed his first Scotland cap.
Now Gallagher says it would be a “dream come true” to line-up against his pal on such a huge stage.
He said: “Andy and I went to school with each other and I reckon there will be a lot of banter going on behind the scenes before the semi-final.
“We’re pretty close friends but there are bragging rights at stake and I would love to play against him.
“He has done so well since going to United. He’s been young player of the month and been linked with moves to big clubs. He’s set a real example for every young player in Scotland.”