Gray, 37, came up through the ranks at Leeds under Hart in the late 1990's, and after successful spells with the likes of Bradford City, Sheffield United, Burnley and Barnsley, Gray made his return to Elland Road in 2012, penning a one-year contract before retiring with Bradford City.
Now, the former striker is one again back at Leeds, working as a coach of the Under-16's as he looks to help nurture and develop the next generation of Leeds prospects.
Speaking to LUTV, Gray explained what he has been telling the players under his control, passing on wise words from his own playing days.
"I remember being told countless times off numerous players to enjoy it, because it doesn't last long and it's over quickly," said Gray. "Fortunately, I played until I was 36, and I've been telling the lads that it goes so quickly, so enjoy every minute, but not only that, try and make the most of it, because it's a great opportunity for all of them."
Gray has now been joined in the youth development staff by his former youth coach Hart, who has returned to Elland Road as the club's academy director.
Gray added that Hart's authority and coaching ability have made him such a success over the years, and believes that his style of coaching is ideal for letting the young players know what they should be doing and how they can improve in years to come.
"I think, mainly his authority and his coaching techniques. He gets his principles across pretty quickly and lays those foundations, so all the players know, in no uncertain terms, exactly what they're doing, and what their roles and jobs are - and hopefully what it takes for them to be a professional footballer," he added.
Gray and Hart will be looking to bring through more young talent, given that academy graduates Charlie Taylor, Sam Byram, Lewis Cook and Alex Mowatt are currently important first team players in the Championship - and the youth development aspect is becoming increasingly important once again at Elland Road, hence Hart's return to the club.