The post featured an old headshot of the "Old Man" during his days in the Navy.
"Today I lost a friend, a father, a teacher and so much more. The Old Man lost his long battle with Parkinson's this morning. Love you Dad. See you on the other side," Rick Harrison wrote.
Harrison shot to reality TV fame when the Las Vegas pawn shop he owned with Rick, Gold & Silver Pawn, became the subject of the History Channel's series Pawn Stars starting in 2009. He was a beloved cast member of the show, known for his grumpy yet lovable personality.
It was Rick's first post since announcing his father's death earlier in the day.
"Richard Benjamin 'The Old Man' Harrison passed away this morning surrounded by those he loved. He will be tremendously missed by our family, the team at Gold & Silver Pawn and his many fans the world over," Rick wrote on Instagram, as previously reported. Harrison was 77.
"He was my hero and I was fortunate to get a very cool 'Old Man' as my dad. That I got to share him with so many others and they got to see what a great family man he was is something I am grateful to have experienced with him," he continued.
"He lived a very full life and through the History television show 'Pawn Stars' touched the lives of people all over, teaching them the value of loving your family, hard work and humor. We appreciate everyone's thoughts and prayers and ask that we are provided some privacy at this time," he concluded his initial post.
Gold & Silver Pawn also announced the "Old Man's" passing in a statement Monday morning.
"It is with heavy hearts that we acknowledge the passing of Richard Benjamin Harrison (known as 'The Old Man' to 'Pawn Stars' fans the world over) this morning," a statement from the business read via its Facebook page. "He was surrounded by loving family this past weekend and went peacefully."
"The team at Gold & Silver Pawn and the Pawn Stars family is grieving his loss. He will be remembered as the best father, grandfather and great-grandfather you could have by his family and by fans as the sometimes grumpy (always loving, however), often wisecracking, and voice of absolute reason on the History television show Pawn Stars. Services are pending and the family appreciates your prayers and kind words."