Tributes have flooded in from across the world of football after the iconic former Gers, Scotland and Everton boss died on Tuesday.
McCoist's career was deeply intertwined with Smith's, first as a player and then as a coach, inspiring untold success together at Ibrox.
During Smith's first spell as Gers boss in the nineties, McCoist became the club's greatest goalscorer of all time and won nine consecutive Scottish Premiership titles.
They were reunited in 2007, as McCoist assisted Smith in the dugout for four triumphant years, before taking the reins himself in 2011.
However, it's the memories off the pitch which McCoist cherishes most.
Looking back on their time together, the former striker recalls unforgettable moments which made Smith so much more than a football manager to him.
"I've got so many memories of Walter," McCoist told talkSPORT. "Brilliant memories, phenomenal memories of the man.
"I'm not just talking about football, I'm talking about on the golf course at Turnberry in Loch Lomond, all these kinds of things, just sitting and having a glass of red. I just used to sit and listen and take it all in.
"I remember we went to Florence, we played Fiorentina in the semi-final of the Europa League in 2008. It went to penalties and he turned round to me and said, 'what's the score?' He didn't even know the score on penalties.
"I looked at him, I thought he was winding me up. I said, 'gaffer, if you don't know the score, if this ball hits the back of the net you're about to find out the score'.
"And of course we stuck the penalty away and it was unbelievable. The two of us were hugging, it was just a memory I'll never ever forget.
"There are so many. I couldn't begin to tell you.
"I remember I took him to AC/DC. He didn't even know what AC/DC were all about. I said, 'Come on you oldie, we're going to Hampden to see AC/DC'.
"Boy did he enjoy that. Air guitars were out and everything, Angus Young was up on stage, he just absolutely loved it.
"He was just great. He loved music. He was not having me in the punk-rock era at all, it was The Beatles and the sixties or nothing - that was the era to be alive.
"He was really, really knowledgeable, fantastic company. We used to go away together and play golf. We used to take the girls away at Christmas for a couple of days, it was usually quizzes and sports quizzes.
"Just wonderful, wonderful memories."
McCoist added: "He was the best, wasn't he? By some considerable distance. For me, I was lucky enough to play under him.
"I was 17 when I first played under him in the Scottish youth team. I can still remember messing about on the balcony in Monte Carlo and he'd give me that look.
"When you say old school, if you'll allow me to say old school, because times have changed, times have moved on. Sometimes I do feel like in some cases, not all cases, we are a bit precious.
"But Walter, the one thing Walter was, he was 100 per cent honest and fair. If he said something to you, he wasn't saying it for effect, he was saying it for a reason. He was saying it because it had to be said.
"He was just the most genuine of men. Hard, fair, honest. Absolutely wicked sense of humour and just brilliant to be around."