Macleod was sidelined for the second half of last season after he contracted a debilitating virus that at one stage started to affect the muscles around his heart.
But the 20-year-old was given the all-clear to resume training by Ibrox medical staff during the summer and has forced his way back into the first team.
The midfielder has netted four goals for Ally McCoist's side in the first six games of the 2014/15 campaign - just one less than he bagged last term.
And Scotland Under-21 boss Billy Stark has included him in his squad for European qualifiers against Slovakia and Luxembourg next month.
Speaking as he promoted a Rangers Charity Foundation initiative with the Scottish Association for Mental Health, Macleod confessed he was surprised at his progress.
He said: "I was definitely chuffed when I heard I had been called up to the Scotland Under-21 squad earlier on this week.
"I am looking forward to the two games.
"I keep going on about it but, after everything that has happened to me in the past six months to a year, it is good to finally be back in the swing of things.
"To get called up is just the icing on the cake.
"In a way, I have been taken aback at how quickly I have got back into things this season. But I think that has probably been the best thing for me.
"I have just been chucked into the thick of things and I have had to get my head around it. That is one of the main things that I was worried about.
"I thought the fact that I had been ill would maybe have preyed on my mind and that would have held me back. But I am happy to be in the thick of things and I am enjoying playing football again.
"I have started off quite well. I have scored four goals already - which is nearly as many as I scored last year. I can't complain.
"Hopefully I can keep it going and over the next couple of months we can go on a run and win more games."
Meanwhile, Macleod has admitted the flak that flew in the direction of the Rangers team after their first three games against Hibs, Falkirk and Hearts has helped them to hit top form.
He said: "When you are at Rangers you are always going to get criticism no matter how you play. There are always going to be people who think you can do it better or a different way.
"But, at the same time, we knew that the performance against Falkirk wasn't good enough and we were all disappointed with the result against Hearts.
"But I felt the Hearts game could have gone a whole different way. If we had taken the chances we created in the first 10 or 15 minutes it would have changed the game completely.
"Of course, we weren't clinical enough and that let them back into it. They beat us fair and square.
"Criticism makes you want to go out, prove your doubters wrong and do better. That is what we have done in the last three games. Hopefully we can continue that."