John was born on September 6, 1990 in Raleigh, North Carolina. Wall is the son of Frances Pulley and John Carroll Wall, Sr. His sister, Cierra, and his half-sister, Tonya was supported by his mother working multiple jobs. He went to high school at Word of God Academy. Wall played his first two years of high school basketball at Garner Magnet High School. After his second season, his family moved to Raleigh and Wall repeated his sophomore year at Needham B. Broughton High School. Despite a very impressive tryout, Wall was cut from the Broughton basketball team for attitude-related issues. As a result Wall transferred from Broughton to Word of God Christian Academy, also in Raleigh.In the summer of 2007, after his sophomore year of high school, Wall was invited to the 2007 Reebok All-American Camp in Philadelphia. .In 2008, Wall played in the Elite 24 Hoops Classic. He scored 10 points and earned co-MVP honors with Dominic Cheek. As a fifth-year senior in 2009 Wall averaged 19.7 points, 9 assists and over 8 rebounds for Word of God Christian Academy and was ranked as one of the best high school basketball players in his class. Wall led Word of God to the North Carolina Class 1A state championship where they were defeated by United Faith Christian Academy 56–53 after United Faith’s Ian Miller hit a 40 foot shot at the buzzer. Wall scored 11 points in the game. He was selected to participate in the 2009 Nike Hoop Summit in Portland, Oregon. He scored 13 points to go along with 11 assists and 5 steals. He was also selected to play in the 2009 Jordan Brand Classic at Madison Square Garden where he notched 6 assists.