The legendary Dolphins quarterback had yet to officially retire despite not playing since 1999, but he signed a one-day contract along with five others on Wednesday and will retire as a Dolphin on Thursday.
"This organization, the team, this city, football, it all means so much to me," Marino said at a press conference. "It's been my whole life besides family. My first love was football. To sign a contract for a day, I'm very proud of it.
"... I just love being a Miami Dolphin. Even if it's for a day, that's fine with me."
The 55-year-old Marino was joined by former Dolphins quarterback Bob Griese, offensive lineman Larry Little, wide receiver Nat Moore, linebacker/defensive end Kim Bokamper and cornerback Sam Madison in signing one-day deals to retire with Miami.
All six played their final NFL game with the Dolphins, but technically ended their careers as free agents.
"In this day and age, we try to get players to retire as Dolphins," Miami executive vice president of football operations Mike Tannenbaum said. "This means a lot to us, our legacy. We're all so proud of it and all the contributions you guys have made, it means a lot to all of us. We thank you guys and we're proud that you're Dolphins."
The six Dolphins stars combined for two NFL MVP Awards, 14 first-team All-Pro and 25 Pro Bowl selections.
Marino ranks fifth all-time on the NFL's passing yards (61,361) and touchdowns list (420) and is the Dolphins' franchise record-holder in both categories over his 17 seasons dating back to 1983. Griese, who spent 14 seasons with Miami, ranks second in both categories (25,092 yards, 192 TD).
"The fact that I've been a free agent for 16 years and no one's called is kind of upsetting to me," Marino quipped.