The 31-year-old “Cooler Than Me” singer -- who embarked on a massive journey traveling from New Jersey to California -- celebrated the big accomplishment on Instagram, where he's been diligently documenting his momentous undertaking.
"My name is Mike Posner and I walked across America," Posner captioned a clip of himself with the ocean water washing over his feet. He concluded the message with the slogan he'd used throughout the entire trip: "Keep Going."
Posner followed the post up with another shirtless clip of himself cheering and celebrating in the sand, which he captioned, "Moments after putting my feet in the Pacific Ocean after walking across America."
The night before his big victory, Posner shared a video excitedly commemorating his accomplishment.
"The shot's all teed up, I just gotta tap it in the hole. Keep me in your prayers tomorrow, keep me in your thoughts tomorrow," Posner excitedly told his followers. "Know that I'm gonna handle my business, finish this this up. Finish what the f**k I started! Keep going!"
On Oct. 16, as he neared the completion of his trip, Posner also reflected on what it meant to him, and what he's learned.
"Guys I’m nearing the end here. It’s time for me to focus up," Posner wrote. "There are lots of people congratulating me and asking me how it 'was' and I’m not even done yet. I don’t even know what this experience means in the context of my life yet."
"I do know that I am not the same person I was when I started. I’m harder. I’m more authentic. I’m more real. I’m more myself," he added. "That’s the only trophy I need. Keep going."
Apart from the obvious challenges of walking nearly 3,000 miles, some of the obstacles Posner faced were truly unexpected -- such as when he got bit by a baby rattlesnake back in August, and had to be hospitalized.
A rep for the musician told ET at the time that Posner had arrived in Colorado when he failed to spot a baby rattlesnake curled up on the ground before it bit his left ankle. He was immediately airlifted to a nearby hospital where he was given anti-venom for the bite, saving his life.
The bite required Posner to return to his home to recover for a number of weeks, which delayed his overall timeline. Upon his return, his daily milage dropped for several weeks as well.
However, through sheer determinism, Posner continued to take his own slogan to heart and kept going until he'd finally reached the Pacific Ocean and completed his wild adventure.