His father, whom Carmelo is named after, was Puerto Rican and his mother African American. His father died of cancer when Anthony was 2 years old. He lived in the small town of Friona, Texas for two years after which his family moved to Baltimore in 1992 where he began winning local basketball awards. He has two brothers, Robert and Wilford, a sister, Michelle, and half-sister, Daphne.

Anthony transferred to Oak Hill Academy in Virginia, and became a high school All-American. He then played for one season at Syracuse University. He averaged 22.2 points (16th in the nation, 4th in the Big East) and 10.0 rebounds in leading the Orangemen to their first ever NCAA tournament title in 2003. He led the team in scoring, rebounding, minutes played (36.4 minutes per game), field goals made and attempted and free throws made and attempted. Carmelo also earned the tournament's Final Four MVP honors - his efforts included a 33 point explosion against Texas in the semi-final, and a solid 20 points and 10 rebounds in the final victory over the University of Kansas. Afterward, the overjoyed Syracuse head coach Jim Boeheim described Anthony as, "...by far, the best player in college basketball. It wasn't even close. Nobody was even close to him last year in college basketball. That's the bottom line." Anthony chose to abandon his collegiate career and declare himself eligible for the 2003 NBA Draft, where he was chosen 3rd overall by the Nuggets, behind LeBron James (1st overall, Cleveland Cavaliers) and Darko Milicic (2nd overall, Detroit Pistons).

In his first year, he averaged 21 points per game and led the Nuggets to one of the biggest turnarounds in NBA history, transforming a previously uncompetitive team into a playoff contender. Anthony narrowly lost Rookie of the Year honors to the Cleveland Cavaliers' LeBron James. He was chosen as a member of the 2004 USA Olympic basketball team.

Before Carmelo joined the 2004 USA Olympic basketball team, he was Punk'd by Ashton Kutcher's crew members for falsely believing that Carmelo's friends trashed the hotel room that was worth $10,000 in damages. After this prank, Carmelo said, "You'll pay for this, Ashton!"

In the summer of 2005 he made a cameo appearance in Ciara's fourth single, off of her debut album, Goodies, entitled And I.

Carmelo's playing style is not considered to be as flashy as that of fellow 2003 draft picks Dwyane Wade and James, but he is generally recognized as a prolific scorer. His movement is smooth, and he is deceptively quick. Anthony has a variety of subtle offensive moves, a consistent jump shot, and an uncanny ability to drive to the basket and earn trips to the free throw line. Along with being a proficient scorer, he is also a good rebounder, and his teammates from Syracuse have described him as an unselfish player. Still, questions remain about his efficiency as a player. His PER was at 16.7 in the 2004-2005 season. Also, in that season, his offensive rating, ORtg, was 103 and his defensive rating, DRtg, was 107. The league average, in the meantime, was 106. This means that when he was on the court, his opponents scored 107 points per 100 possessions and his team scored 103 points per 100 possessions. Other metrics, including the Roland Rating as well as On/Off court measures peg him as inefficient as compared to his peers such as LeBron James and Dwyane Wade.

However, his on-court feats have been somewhat over-shadowed by off-court troubles. He was charged with misdemeanor drug possession in October 2004, after airport inspectors found marijuana in his backpack. The charge was dropped after a friend said the marijuana was his. In November, three men were arrested on suspicion of trying to extort $3 million from Anthony with a videotape of a bar fight that broke out after someone spilt a drink on Anthony's now-fiancée, MTV personality La La Vasquez, in New York City in September. Later that year, footage of Anthony hanging with an entourage appeared on a video called Stop Snitchin' distributed in urban Baltimore, Maryland, casting the player as being in favor of death or violence against those who "snitch" on drug dealers to local law enforcement. Anthony claimed he was set up and he did not condone violence against police informants.

Anthony's former penthouse condo in Denver's Golden Triangle neighborhood was featured on the show MTV Cribs. His current home also was featured on MTV Cribs.

Anthony became engaged to hip-hop artist Alani Vasquez (La La Vasquez) on Christmas Day, December 25, 2004.

Anthony wears the number 15 on his jersey. According to his official site, “My original number was 22 but when I went to Syracuse that was retired for Dave Bing. So I switched to 15 and then that become my number.”

Anthony has also acquired a reputation for being a tremendous performer in the clutch. During the time period from the beginning of the 2003-2004 regular season to the end of the 2005-2006 regular season, he hit 11 out of 17 game winning shots, by far the most of any player (next was Ray Allen who hit 8 out of 18 game winning shots). His shooting percentage for game winners was .647, the highest of any player with 4 or more game-winners. Kobe Bryant, a player who is often lauded for his performance in clutch situations, hit 7 of 32 game winning shots, and Carmelo's draft-mates Wade and Lebron hit just 6 of 17 and 4 of 19, respectively.

Anthony is the spokesman for several companies. His major sponsorship is with Nike, Inc.'s Michael Jordan line of shoes and apparel. He has had two signature shoes: the Nike Jordan Carmelo 1.5 and Air Jordan Carmelo 5.5.

Anthony's current season high points score is 45 against the Philadelphia 76ers.

He also co-owns the Carmelo-Hemelgarn Indy car racing team, whose lone driver is P.J. Chesson

Anthony was named to the 2005-06 All NBA Third Team.