Smith scored a hat-trick at home as his Beckett Football League Division 1 side fought back 2-1 to defeat 10-man United, who ply their trade in Division 2.
The victory came just days after Sleighs’ 2-0 victory in the Gordon Harrison Memorial Trophy final against Kirkby.
Smith said: “Monday night was bittersweet for me as I think it was potentially my last game for the club – as I’m hoping to travel.
“But I couldn’t be happier to complete the cup double on our hometown ground in a local derby and score a hat-trick on top of that, well, it doesn’t really get any better!”
“You have to give credit to Goldsborough, they made us work for it, hats off to them and good luck on Friday night (in their Panasonic Cup final with Ayton).”
Ed Turner, on his final game as Sleights manager, added: “I’m delighted the guys are coming out on top in a big game and retaining the cup.
“I’m so happy that Charlie Smith scored a hat-trick and took our guys to victory.
“I’m also delighted that Liam and Joe scored a goal in front of a great turnout and I’m so proud of my boys.
“Thanks to Goldsborough for making it a battle.”
Sleights chairman Andrew Snaith said: “It was a great game of football and I was delighted to see the town come out again to support two teams of local lads.
“I thought the scoreline was a little misleading because it was closer than that and Goldsborough played their part throughout. Hopefully they can win their final at Pickering Town on Friday night.
“I am delighted for Ed Turner, our outgoing manager, without him none of the successes we have had would have happened.”