Casey was selected by the fans through the modern-player ballot, while Driessen and Reilly were elected by the veterans committee, which is comprised of Reds Hall of Famers, media members, historians and Hall of Fame executives.
More than 2,000 players have worn a Reds uniform since their founding in 1881, but only 81 have earned the famous red jacket.
"I am so proud to be going to this Hall of fame," Casey said. "I can't thank you enough. I was so proud to say I was a Cincinnati Red. I will always be a Cincinnati Red and I am so proud to be a part of this organization."
While the results Sunday afternoon at Great American Ball Park weren't favorable for Cincinnati, it would take more than a loss to dampen the mood at the Duke Energy Convention Center.
More than 1,400 Reds friends, family and fans were in attendance Sunday night, including 55 current and former players and coaches. The crowd marked the highest attendance at any Reds Hall of Fame Gala.
The ceremony featured a silent auction benefiting the Hall of Fame museum, dinner and drinks, as well as interviews and speeches from current Reds Hall of Famers like Eric Davis, Johnny Bench and Joe Morgan.
But the fans got more than just a scripted ceremony -- a spoof video of Casey's eccentric personality entertained the audience, former greats shared old clubhouse stories and third baseman Todd Frazier even put his Sinatra vocal skills on display.
Reilly, who played eight years in Cincinnati as the team's starting first baseman from 1883-1891, hitting .289 in 10 total years in the Majors, was represented by his great great great great nephew Kirtley Kinman.
While Kinman never got to see his late relative suit up, the pride for the inductee was visible.
"John Reilly's family is so proud of the legacy that he left to this sport and this town," Kinman said.
A teary-eyed Driessen addressed the crowd next after an introduction from his daughter, Dominique.
Driessen joined the Reds as an 18-year-old undrafted free agent in 1969 before becoming a vital part of the Big Red Machine, which dominated baseball in the early-to-mid '70s.
The first baseman won five National League West Division titles, four National League pennants and back-to-back World Series titles in 1975-76, and reminisced on his days playing with fellow legends like Bench, Morgan, Pete Rose and Tony Perez.
"Being part of the Big Red Machine was truly special," Driessen said. "You couldn't help but to pick up in how to win ball games."
The night was extra special for Driessen, who was also celebrating his 36th wedding anniversary with his wife.
"This is a dream come true for me," said Driessen, now 60. "I feel honored to be recognized today. This really is the best baseball city in America."
Casey lived up to his status as "The Mayor," entertaining the crowd for nearly 30 minutes with a number of different comedic stories, memories and thank you's.
He played in Cincinnati for eight years, developing into a three-time All-Star in 1999, 2001 and 2004, playing in 1,075 games as a Red with a career .305 batting average.
The local hero left the fans with one final message before the ceremony closed.
"Thank you, thank you, thank you," Casey said. "It was such a neat thing to come out and just be back here in Cincinnati. I know every day I came out and had Cincinnati across my chest, I played for this city."