The Hoops were in sublime form as they cruised to an 8-0 win over Queen of the South to complete a third successive league and cup double at Under-19 level.
McGeough stepped back down to the Parkhead kids squad after his time with Neil Lennon's first team and Kennedy was delighted with a superb Hampden showing from the midfielder.
He said: "Through the season, the team has been exceptional. In my time here, it has been the best bunch I have seen for a while. Tonight, I thought it was a team performance and we had goals coming from everywhere.
"Dylan showed a great attitude coming back from first team duty to come in and step up to the plate. He came in and gave us a different dimension. Everybody was excellent but I thought Dylan had a big part to play in that."
Kennedy's side went into the game as strong favourites to lift the silverware and were ahead after just 62 seconds as Filip Twardzik found himself in the right place at the right time to stab the ball over the line following a Hoops corner.
It was a dream start for the Parkhead proteges and they never looked back as they fired in another three goals before the break to put their name on the cup in impressive style as Queens struggled to cope on the Hampden stage.
After 29 minutes, two of Celtic's standout men combined to double their advantage. Dylan McGeough fired in a low corner from the right hand side, with captain Jackson Irvine connecting perfectly to rifle the ball past keeper Jim Atkinson.
Stuart Rome's side were never in the game and the scoreline soon got worse for the Queens kids as Celtic netted twice in two minutes before the half-time whistle.
First, McGeough embarked on a superb mazy run from outside the box and slotted the ball into Atkinson's net before Callum McGregor stroked home from the spot after Darnell Fisher was felled inside the area.
The break offered Queens some respite from the Celtic onslaught but things soon went from bad to worse as their Hampden dreams turned into a nightmare.
John Herron was next to add his name to scoresheet with a neat finish from just inside the area before McGeough enhanced his reputation with another fine individual effort.
The forward was to be denied his hat-trick as he was replaced by Bahrudin Atajic but did his chances of more first team action no harm with a fine display.
Four minutes later, McGregor got his second of the night, converting James Alabi's cross as the Hoops eased their way into the record books, eclipsing Rangers 5-0 win over them in 2007. He soon completed his hat-trick, netting from the spot after a foul on Alabi.
Kennedy added: "It is great for us to win things at youth level but the most important thing for us is to get players into the first team. That is what we are judged on at the end of the day, not how many league and cups we win at Under-19 level."