"In the last month I've dealt with two life changing events back to back. My decision to move on from basketball and the tragic passing of Big Rich," Jefferson wrote. "The support of my family and friends have been huge."
Jefferson played 17 seasons in the NBA, winning a championship with the Cleveland Cavaliers in 2016 as a key role player off the bench. The 38-year-old averaged 8.2 minutes per game in 20 appearances with the Denver Nuggets last season and has also played for the Nets, Bucks, Spurs, Warriors, Jazz and Mavericks.
Richard Jefferson Sr. was killed in a drive-by shooting in California on Sept. 19, according to the Los Angeles County Sheriff's Department.
Jefferson and his father had grown closer in recent years, sources told ESPN's Dave McMenamin last month, with Jefferson, his wife and two children spending their summers in Los Angeles' South Bay, not far from Jefferson Sr.'s home in Inglewood.
"He really was a true OG," Jefferson wrote about his father. "I'm going to miss all his one-liners, his cooking and his ability to make a whole room laugh."
Before his announcement Saturday, the younger Jefferson had started to pursue a post-playing career in broadcast journalism, appearing on ESPN and other networks.