Harrell was born on January 26, 1994 in Tarboro, North Carolina. He spent his high school career with two schools. He first started his career at North Edgecombe High School and joined Hargrave Military Academy after that.
Initially Harrell had agreed to play college basketball at Virgina Tech, but later he chose to play for Louisville as the coach of Virginia Tech was fired. He played as a power forward in his college. In his freshman year, Harrell averaged 5.7 points and 3.6 rebounds in 16.2 minutes per game. Towards the end of his first season, he scored 20 points against Syracuse in the Cardinals' Big East Conference championship. He helped the Cardinals to win the 2013 NCAA Championship. Players and fans of his team expected a lot from him after his fellow team mate Gorgui Dieng departed for the 2013 NBA Draft. Harrell had also a good sophomore season. In his sophomore season, he achieved his 10th double-double of the season with 22 points and 11 rebounds in the AAC Championship game against Connecticut. He also scored a career-best 25 points, hitting a career-high 11 field goals against Memphis. In that match, he also grabbed 12 rebounds and made 3 steals. On December 9, 2014, Harrell set a new record to become the all-time leader in dunks in Louisville basketball history in a match against Indiana University. His record of 163 career dunk mark passed Pervis Ellison’s record of 162 career dunk made in 1988. Farrell has a 7 ft 6 inches wingspan. His wingspan creates problems for his opponents, however his weakness lies in his shooting. He hit only 59.7% of his shots at the charity stripe in 2014-15, which was career high figure for him, but indeed is not convincing number. As per basketball analytics company, DraftExpress, Harrell was once in number 2 rankings among NCAA juniors and was number 18 overall for the 2015 NBA Draft. He also took part in FIBA U18 World Championship as one of the players of team USA.
Farrell is not married yet and he does not have any children as of 2015. However there are news that, he is currently dating Randi Ewing, daughter of retired basketball player, Patrick Ewing. The couple are going through strong relationship and there are not any rumors of break up till now.
Farrell stands 6ft 8 inches tall and weighs 109 kg. That makes his physique huge. Farrell won the 2013 NCAA Championship while he was in college. He was also named in All-AAC First team of 2014 and All-AAC Second team of 2015. Farell recently won the Karl Malone Award in 2015. He is just in the beginning phase of his professional career, so several awards and honors are waiting for him if he keeps improving. There are not much details about his net worth and his salary earnings.