Michael Sheridan went 4-for-4 with a three-run homer and Matt Buschmann pitched seven solid innings as Montgomery cruised to an 11-4 division-clinching win over the Huntsville Stars.
Montgomery (38-30) finished second behind Mobile in the first half but prevailed in the second half as second-place Jacksonville was eliminated.
"I think in April we had a 10-15 record, came out of the chute a little slow, and from then on, May to September, we had one of the best records in the league," Biscuits manager Billy Gardner said. "They came together, the clubhouse chemistry was good with this team. They stay together, compete well."
Montgomery leads the league with 634 runs scored and a .730 OPS. Omar Luna tops the circuit with a .314 batting average, while Kyeong Kang slugged a team-leading 14 homers. Sheridan led the Biscuits with 58 RBIs.
Additionally, Rays' top prospect Hak-Ju Lee ranks fourth with 37 stolen bases and compiled a league season-high 21-game hitting streak from June 17-July 11.
On the mound, Kyle Lobstein (8-7, 4.06) and Alex Colome (8-3, 3.48) anchored the rotation with Buschmann, who gave up two runs on six hits while striking out five in Saturday's clincher.
"The thing about this group was they wanted to win the second half. They were determined to do it," Gardner said. "We had a run for our money with Pensacola and Jacksonville, they put some pressure on us. We could have easily caved in but didn't. It's a testament to the character of the club, a very resilient group."
It's the first playoff appearance for Montgomery since winning back-to-back Southern League championships in 2006-07.
Pawtucket 2, Scranton/Wilkes-Barre 0
The Red Sox secured the IL Wild Card as Nelson Figueroa gave up four hits and struck out six over eight innings. Josh Fields worked a perfect ninth for his fourth save.
Dan Butler provided the offense for Pawtucket, hitting solo homers in the sixth and seventh. Gameday box score
Trenton 3, Binghamton 2
Adonis Garcia went 4-for-4 with three doubles and an RBI out of the leadoff spot and David Adams and Addison Maruszak drove in the other runs as the Thunder wrapped up the Eastern Division title.
Craig Heyer held the Mets to a run on six hits while striking out four over five innings for the win. Gameday box score
Wilmington 5, Potomac 1
Royals' No. 13 prospect Jason Adam yielded a run on two hits and two walks with four strikeouts over six innings to pitch the Blue Rocks to the Northern Division second-half crown.
Brett Eibner hit his 15th homer and Matt Fields added his 17th for Wilmington. Box score
New York-Penn League
Hudson Valley 2, Aberdeen 0
Matthew Spann gave up three hits over six innings to help the Renegades finish off the McNamara Division race.
Marty Grant delivered an RBI double and Joel Caminero went 2-for-4 and drove in Hudson Valley's other run. Box score
Vancouver 4, Yakima 1 (11 innings)
The Canadians completed their comeback in the West Division, reeling off a fourth straight win to capture the second-half title.
Derrick Chung tripled in a pair of runs in the 11th, then scored on a wild pitch to pad the lead. Zack Breault allowed one hit over two scoreless innings to secure the victory. Box score