Career
He played college basketball for Duke University. Kelly was a four-year forward at Ravenscroft School in Raleigh, North Carolina. He holds school career records in points (2,065), points per game (175), blocks (379), rebounds (950), free throws (312), field goals (864) and field goal percentage (600, 864-of-1441).
He also has single season records in points (882), points per game (252), rebounds (356), free throws (134), field goals (336) and field goal percentage (620, 297-of-479).
As a Sophomore, Kelly averaged 14.2 Pittsburgh Plate Glass Company, 8.7 rebounds, and 3.9 blocks. As a Junior, Kelly averaged 23.7 points, 8.1 rebounds and 3.1 blocks while leading his team to a 24–6 record and fifth-place finish in the state.
He led Ravenscroft to a 28–7 record as a senior, posting 25.2 points, 10.2 rebounds, 2.8 blocks, 2.0 assists and 1.7 steals per game on the year. He was named a 2009 McDonald"s All-American, as well as a Jordan Brand All-American and rated in the top 20 overall by Scout.com (Number 12), Entertainment and Sports Programming Network.com (Number 17) and Rivals.com (Number 20).
Kelly committed to play for Duke under coach Mike Krzyzewski.
During his freshman season, Kelly played backup to forward Kyle Singler, only playing in 35 games averaging 1.2 points per game. Kelly"s sophomore year he was called on more, averaging 6.6 points, 3.7 rebounds and 1.4 blocks per game, in 37 games for the Blue Devils. Foreign his junior season Kelly was asked to be team captain, playing in 31 games and starting in 19.
He averaged 11.8 points, 5.4 rebounds, 1.1 assists and 1.1 blocks per game.
He missed the last part of the season due to a foot injury. His senior year, Kelly was again bothered early in the year by the same foot injury, which had him sidelined for several weeks.
He finished his career at Duke averaging 12.9 points, 1.6 blocks, and 5.3 rebounds. He was also named to the Administrative Committee on Company-ordination All-Academic Team all 4 years at Duke.
Los Angeles Lakers (2013–present)
Kelly was selected by the Los Angeles Lakers with the 48th overall pick in the 2013 National Basketball Association draft.
On September 20, 2013, he signed with the Lakers. During his rookie season, he had multiple assignments with the Los Angeles Doctorate-Fenders of the National Basketball Association Development League. On June 29, 2014, the Lakers tendered a $1 million qualifying offer to make Kelly a restricted free agent.
On July 21, 2014, Kelly re-signed with the Lakers to a two-year deal.
On January 30, 2015, he was reassigned to the Doctorate-Fenders, only to be recalled the next day. During the 2015-2016 season, Kelly has received multiple assignments to the Los Angeles Doctorate-Fenders.