Monfort was recruited to join the
Ateneo Blue Eagles by Coach
Norman Black, who asked him to first join their scrimmages in
Silay City in
Bacolod. As a result, he was not part of the Ateneo roster that won the UAAP championship in 2008. He got to play with the main team again during the
Unigames later that year, which Ateneo won. In 2009, Monfort was set to spend another year with Team B, but a player was suddenly deemed ineligible on Ateneo's main team which opened up a slot for him to return. That year, Ateneo defended its UAAP title as he contributed as
Jai Reyes's backup. Ateneo also won the
Philippine Collegiate Champions League (PCCL) title and defended its Unigames title that year. For
Season 73, with Reyes graduated from college, Monfort succeeded him as Ateneo's starting lead guard. In a win over the
Adamson Soaring Falcons, he made six straight clutch free throws to seal the win. In the Final Four, he scored 22 points on 7-of-9 shooting and made all three of his three-point attempts to get Ateneo past Adamson and into the Finals. In Game 2 of the Finals, he scored 10 points as Ateneo won its third straight title thanks to a game-winning three-pointer from
Ryan Buenafe. To finish the year, Ateneo successfully defended its PCCL title. During the preseason, Ateneo won the
Filoil Flying V Hanes Preseason Premier Cup. The Eagles began
Season 74 with a win over Adamson in which Monfort made two clutch free throws with 16.3 seconds remaining to seal the victory. He then scored 10 points in a win over the Archers. In a win over the Maroons, he scored 13 points. Ateneo finished the first round of eliminations with no losses. In the second round of eliminations, he scored 13 points in a win over the Archers. Ateneo had a chance to sweep both elimination rounds but in their final game of the season, they lost to Adamson. After getting past UST in the Final Four, they faced the
FEU Tamaraws in the Finals. In Game 1, he contributed 11 points, five rebounds, five assists and two steals in a win. Ateneo also won Game 2, making them champions for the fourth straight year. In his final year, he graduated as the UAAP leader in assists and free throw percentage. ==Professional career==