Finney-Smith attended I. C. Norcom High School in Portsmouth, Virginia. As a junior in 2009–10 playing for the school's basketball team, he averaged 19.7 points, 13 rebounds, six assists, three steals and two blocks per game. In September 2010, Finney-Smith committed to Virginia Tech, and later signed a National Letter of Intent with the Hokies in December. As a senior at Norcom in 2010–11, Finney-Smith averaged 18 points, 10.7 rebounds and 3.8 blocks per game. He led the team to back-to-back Group AAA championships, along with Eastern Region and District titles. He recorded 19 points, 17 rebounds and three blocks in the state championship game as a senior. He finished his high school career as a two-time VHSL Class AAAPlayer of the Year and first-team all-state, all-region, All-Tidewater and all-district. He also earned All-Tidewater player of the year as a junior and co-player of the year as a senior.
College career
As a freshman at Virginia Tech in 2011–12, Finney-Smith played in all 33 games, making 30 starts. He averaged 6.3 points and 7.0 rebounds per game and was named to the ACC All-Freshman Team. He scored a season-high 17 points in a 66–65 win over Boston College. In June 2012, Finney-Smith transferred to Florida and was forced to sit out the 2012–13 season due to NCAA transfer regulations. As a sophomore in 2013–14, Finney-Smith was named SECSixth Man of the Year, becoming just the second Gator to win the award after Chris Richard in 2007. He was Florida's leading rebounder, both in total rebounds and per-game average. He also recorded the first 20/15 performance by a Gator in a road game during Billy Donovan's tenure, totaling a personal-best 22 points in an overtime win over Arkansas. He appeared in 37 games with two starting assignments, averaging 8.7 points, 6.7 rebounds and 2.1 assists in 25.8 minutes per game. As a junior in 2014–15, Finney-Smith was named second-team All-SEC by the coaches and was Florida's leading scorer, rebounder and three-point shooter. He scored a career-high 25 points in Florida's win over Jacksonville, including a 5-for-7 performance from three-point range. As a senior in 2015–16, Finney-Smith was named second-team All-SEC by the coaches and third-team All-SEC by the Associated Press. He was Florida's leading scorer for the second straight season and top rebounder for the third consecutive season. He became the first Florida player to join the 1,000-point club after transferring to the school mid-tenure. His 1,220 career points at Florida rank 36th in school history.
Professional career
After going undrafted in the 2016 NBA draft, Finney-Smith signed with the Dallas Mavericks on July 8, and joined the team for the 2016 NBA Summer League. Finney-Smith secured an opening-night roster spot after impressing the Mavericks during training camp and preseason. After playing less than five minutes cumulatively over the first five games of the 2016–17 season, Finney-Smith played 31 minutes on November 6 against the Milwaukee Bucks, including most of the second half and overtime. He subsequently recorded five points, three rebounds, three steals and one block in an 86–75 win. Two days later, he made his first career start, scoring five points in a 109–97 win over the Los Angeles Lakers. On December 9, he had a season-best game with career highs of 12 points and eight rebounds in a 111–103 win over the Indiana Pacers. On December 12, he had career highs in points and rebounds for the second straight home game, finishing with 13 points and nine boards in a 112–92 win over the Denver Nuggets. On December 18, he had a team-high 17 points in a 99–79 win over the Sacramento Kings. On March 10, 2018, Finney-Smith played in his first game since November 12, 2017, after missing 51 straight games and 57 overall with left knee quadriceps tendinitis. He had seven points in 18 minutes in the Mavericks' 114–80 win over the Memphis Grizzlies. On July 11, 2019, he re-signed with the Mavericks.
