Butler confirmed the decision in a post for the Players' Tribune.
"Playing in the NBA was a dream—I got to spend 16 years with all of these great teammates and coaches," he wrote. "It was better than I ever could've imagined. I may be retiring from the game, but I'll stay close to it. I'll be around it in some form or another."
The Miami Heat selected Butler with the 10th overall pick in the 2002 draft. He embarked on a journeyman career, making stops with the Los Angeles Lakers, Washington Wizards, Dallas Mavericks, Los Angeles Clippers, Milwaukee Bucks, Oklahoma City Thunder, Detroit Pistons and Sacramento Kings.
The University of Connecticut product last played with the Kings during the 2015-16 season but waited nearly two years since his release in July 2016 to officially retire.
His long, winding career path allowed him to interact with people from around the country, and he mentioned the impact of that in his Players' Tribune announcement:
"And to the fans—you will never know the joy you brought me. Thank you. I hope that when you think of the name Caron Butler, you remember how much I loved and respected the game. I hope you have an image of a guy who gave it everything he had, physically and mentally. I know it's a cliche, but this really was more than a game for me—it was what saved me from a very grim future."
Butler averaged 14.1 points, 5.0 rebounds, 2.3 assists and 1.3 steals across 881 regular-season appearances. He also played in 65 playoff games.
The Wisconsin native's resume also includes two All-Star Game selections and an NBA championship with the Mavs in 2011.