South Putnam reached the final after knocking off Cloverdale 46-34, while Greencastle defeated the hosts 39-22 in the opening game.
The Tiger Cubs opened up a large cushion in the game after outscoring the Eagles 14-2 in the second period for a 28-11 halftime lead.
South Putnam rallied in the fourth quarter, outscoring the Tiger Cubs 17-8, but had too much ground to make-up as time ran out.
Colyn Foxx led all scorers with 14 points for Greencastle, with Adam Gerard chipping in nine. Kinser Franklin led the Eagles with 11, with Klayton Vittetow and Jacob Schroer adding seven each.
Greencastle JV head coach Doug Hudson said afterward the team was rewarded for its work this season.
"In the game with North Putnam, I thought our defense played well, taking North out of their offensive rhythm. We took them out of their game early, scored in transition and built up a sizable lead," Hudson said.
"Against South Putnam, I thought we played really well in the first half. We held them to one shot on their possession and built up a sizable lead.
"But you have to credit coach (Chris) Jones and his group. They didn't quit and they actually outplayed us in the second half. We were tough enough to make plays when we needed to and pulled out a win."
Hudson noted two individuals in particular for their stand out performances.
"Holden King is our leading scorer and he didn't score in the first game. North Putnam played to take him out of the game and we asked him to be a decoy. He accepted that, not concerned about himself but about the team," Hudson said.
"Colyn Foxx had been playing spot minutes for us this year. Today, he scored eight points in the first game and 14 in the final. He hit several critical shots for us.
"If these guys didn't do those things, we may not win the championship game or even make it to that game. The team as a whole played well, but without those individual efforts, the whole day could have been very different," Hudson added.
Hudson said the squad itself has done better than many might have expected.
"This has been a resilient group. We're playing with seven freshmen and one sophomore, and they come to work day every day. They've impressed me with their defensive tenacity and work ethic," Hudson said.
"I've been coaching a lot of years and these guys give 110 percent effort whether it's in practice or in games. The guys that coached them beforehand have made them the players they are right now.
"We set three goals for this year, which I didn't tell them. First, we wanted to win the conference, which we did with a 5-0 record," Hudson said.
"Second, we wanted to win this tournament, which we did today. And third, we wanted to win double-digit games, which we also accomplished today," Hudson added.
"Not a lot of people thought that this group could win 10-12 games. They've never let that get to them and responded well as the season has gone along.
"We've got four games left and hopefully we'll win them all. It would be great to see this group win 13 or 14 games this year."
At North Putnam
Putnam County Boy's JV
Basketball Tournament - Final
South Putnam 9 2 10 17 -- 38
Greencastle 14 14 8 8 -- 44
South Putnam -- Franklin 11, Vittetow 7, Schroer 7, Russell 6, Humbarger 4, Lorian 2, Taylor 1
Greencastle -- Foxx 14, Gerard 9, King 5, Nicholson 5, Hughes 4, Winslow 4, Bollman 1