The son of Greg Anthony, who played 11 seasons in the National Basketball Association (NBA), he grew up in Manhattan, New York and attended Archbishop Molloy High School before transferring to Oak Hill Academy for his final year.

As a senior, he earned USA Today All-USA first team honors and was named most valuable player (MVP) of the McDonald's All-American Game, Jordan Brand Classic, and Nike Hoop Summit.

In his freshman season at North Carolina, Anthony earned third-team All-ACC accolades despite missing six weeks due to injury.

In 2018, Anthony led the United States to a gold medal and was named to the all-tournament team at the FIBA Under-18 Americas Championship in St. Catharines, Ontario.

[1] In his childhood, he worked with private basketball trainers and played pick-up games at local parks, seeking out older opponents.

[2][5] From a young age, Anthony was coached by Steve Harris, who mentored NBA player Kemba Walker and was a prominent Amateur Athletic Union (AAU) figure in New York.

Christ the King Regional High School head coach Joe Arbitello called Anthony "the best point guard I've seen since Stephon Marbury at that age.

"[7] Anthony averaged 16.9 points and 6.7 rebounds per game and garnered All-Catholic High School Athletic Association (CHSAA) Class AA second team recognition.

[8] As a sophomore, Anthony led Molloy to the CHSAA Class AA city championship finals, where his team was upset by Cardinal Hayes High School.

[10] Anthony averaged 20.7 points, 7.8 rebounds, and 5.8 assists per game and was named to the All-CHSAA Class AA first team with teammate, junior Moses Brown.

[18] In July 2018, Anthony won the most valuable player (MVP) award with the PSA Cardinals in the Nike EYBL after averaging 26.9 points, 7.6 rebounds, and 3.5 assists over 16 games.

[33] By the end of his high school career, he was by consensus a five-star recruit, top-five player, and the number one point guard in his class.

[34] Sources: On November 6, 2019, in his regular-season debut for North Carolina, Anthony had 34 points, 11 rebounds, and five assists to lead his team to a 76–65 victory over Notre Dame.

[38] On November 11, Anthony was named ACC Player and Freshman of the Week after averaging 27 points, 10.5 rebounds and 4 assists in wins over Notre Dame and UNC Wilmington.

[43] A week later, in a game against Virginia, he fell to the floor and began gushing blood from his head after being struck by an opposing player's elbow.

[44] On March 2, Anthony was recognized as ACC Freshman of the Week a second time after averaging 22 points, six assists and 3.5 rebounds per game in victories over NC State and Syracuse.