After attending Selwyn House School and Dawson College in the Montreal, Quebec area, Anthony was recruited by Pensacola Junior College] in Pensacola, Florida, U.S.. After two years, he transferred to the University of Nevada, Las Vegas (UNLV). He led the team in blocks in his junior season in 2004–05; fourth overall in the Mountain West Conference[ but redshirted the next season and did not play. Returning to help lead the Runnin' Rebels to a 30–7 season his senior year (2006–07), he was named MWC defensive player of the year after finishing second in the NCAA's Division I in blocks-per-40-minutes (6.77). (The D–I leader, Mickell Gladness, later became Anthony's Miami Heat teammate.) The highlight in Anthony's senior year was his only double-double of the season, a season-high 13-block, 11-rebound effort versus Texas Christian on February 7, 2007
Anthony signed a one-year deal (with an option for a second) with Miami in July 2007. He made 24 appearances that season, averaging 3.5 points and 3.9 rebounds. The following year Anthony made his NBA playoff debut during Miami's first round series with the Atlanta Hawks. Miami lost the series 4–3. He was re-signed by the Heat in July 2009.
With Miami's high profile free agent signings of LeBron James and Chris Bosh in July 2010 much hype surrounded the team with its new self-proclaimed "Big Three". On July 16, 2010, Joel Anthony re-signed with the Miami Heat on a five-year, $18 million deal. Miami finished the 2010–11 NBA season second in the Eastern Conference behind the Chicago Bulls with a 58–24 record. The Heat cruised through the first three rounds of the playoffs before losing to the Dallas Mavericks 4–2 during the 2011 NBA Finals. Anthony averaged 1.3 points, 3.5 rebounds and 20.5 minutes per game during the NBA Finals.
The following season, Joel won his first NBA title with the Miami Heat against the Oklahoma City Thunder.
Anthony won his second championship on June 20, 2013, when the Heat defeated the San Antonio Spurs in an intense seven game series.
Joel Anthony is commonly referred to as "The Warden".