He died at Frimley Park Hospital last Friday after his heart began to race and he became breathless. The cause of death was given as coronary heart disease.
Jamie, whose parents were Stephen and Leslie Mackay, had a brother Wayne, 24, and sister Ashleigh, 18.
Mr Mackay said Jamie lived for three things — his family, his girlfriend Ellen Bristow and his five-year-old son Liam, who he did not see regularly but who he loved dearly.
He had a passion for football and rarely missed a Shots game, becoming a regular face along with his dad on the East Bank at the Recreation Ground.
Jamie also liked Manchester United and loved watching Wayne play for Farnham Park and Hale.
The brothers played computer games together and Jamie loved golf and music, especially Queen's Bohemian Rhapsody.
Mr Mackay said: “On Thursday he went to pick up his girlfriend, who he'd been with for about nine months.
“She was his soulmate and he wanted to marry and have kids with her.
“After returning home Jamie was taken to hospital because he had become breathless.”
Jamie's pulse was measured at 189 beats a minute, three times the normal rate. He was kept in overnight and last Friday morning concerned medical staff phoned Mr Mackay and asked him to come to the hospital as Jamie's situation had become serious.
Mr Mackay said: “All he ever wanted to do was watch Aldershot with his dad, and with his brother sometimes. We went to every home game and most of the away games.
“When those two goals went in against Cambridge on Saturday he would have absolutely loved it.
“Another thing you always knew with Jamie, if there was ever anyone on TV — a pop star or a football star, anybody that you didn't know their name — you could ask Jamie and he'd be able to tell you.
“He didn't complain about anything, even when they were sticking needles in him and prodding him before his operation. That's how brave he was, he was a very special boy.
“When they took me into the office and told me what had happened it was like a sledgehammer, there's no other way to describe it.”
Wayne said: “We did absolutely everything together. I feel half-empty now.
“He was just such a good boy. He wouldn't hurt a fly and he didn't have a bad word to say about anybody.
“All he ever wanted was to play football and he couldn't ever really do that.
“He knew he had this illness but he enjoyed life to the maximum and he was always happy. He always had a smile on his face.”
Tomorrow (Saturday) morning Aldershot supporters will play Jamie's friends and family in a special match for him at Bourley Road.
Jamie's funeral will take place at St Michael's Church in Aldershot at noon on Wednesday and Shots fans are welcome to wear the team's colours.
He will be buried in Redan Hill Cemetery.
Picture: From left: Jamie Mackay, his brother Wayne and father Stephen
With thanks to the Aldershot News.