Heading into the final frame, the Marlins were on the verge of their 13th straight loss.
After what was a solid five-inning outing from Marlins starting pitcher Tyler Phillips, who gave up two runs on three hits with two walks and five strikeouts, Philly had a four-run top of the sixth inning to take a 6-5 lead.
They would add some insurance during the top of the eighth inning after Bryson Scott knocked his sixth triple of the season to make it 7-5.
Miami's Heriberto Hernandez hit a single with bases loaded and no outs to tie things up 7-7 in the bottom of the ninth. Xavier Edwards would follow up with a single to load the bases once more before Conine finished things off just a couple of batters later.
Despite the Marlins getting the best of Phillies starter Zack Wheeler, who is in the midst of a career season, things started to look bleak as Philly returned the favor after teeing off on reliever Cade Gibson.
During their losing streak, the Marlins were outscored 59-30, scoring more than three runs in a game just two times during the 12-game span.
The last time the Marlins scored eight runs was their previous win against the Seattle Mariners (8-4) on July 9th. Following a home run by Conine in the second and now the walk-off, he could be the guy that turns the rest of the Marlins' season around with the streak over.
The Marlins were one of the better teams in the National League, posting a 20-6 record in June and were 10 games over .500 (52-42). Now, they sit at 7-14 in July and are three games back of the Wild Card spot with a 53-54 record.
Miami were originally on a six-game win streak, also winning 13 of their last 15, before entering their historic slump.
Their Triple-A affiliate, the Jacksonville Jumbo Shrimp, are also on a 12-game losing streak.