Washington Wizards (2011–2012) On June 23, 2011, Mack was selected with the 34th overall pick in the
2011 NBA draft by the
Washington Wizards. On December 9, 2011, he signed with the Wizards following the conclusion of the
NBA lockout. On February 1, 2012, he scored a then career-high 12 points in a 109–103 loss to the
Orlando Magic. In July 2012, Mack joined the Washington Wizards for the 2012 NBA Summer League. On October 28, 2012, he was waived by the Wizards.
Maine Red Claws (2012) On November 2, Mack was selected with the fourth overall pick in the
2012 NBA Development League draft by the
Maine Red Claws.
Return to Washington (2012–2013) On December 25, 2012, Mack re-signed with the Wizards, but was again waived by the team on January 7, 2013.
Return to Maine (2013) On January 9, 2013, Mack was reacquired by the Red Claws.
Philadelphia 76ers (2013) On January 17, 2013, Mack signed a 10-day contract with the
Philadelphia 76ers. On January 28, he signed a second 10-day contract with the 76ers. He was not retained by the 76ers following his second 10-day contract,
Third stint with Maine (2013) On February 7, 2013, Mack was reacquired by the Red Claws. He went on to play for the Futures All-Star team in the 2013 NBA D-League All-Star Game.
Atlanta Hawks (2013–2016) in November 2013 On March 6, 2013, Mack signed a 10-day contract with the
Atlanta Hawks. On March 16, he signed a second 10-day contract. On March 26, he signed a two-year, non-guaranteed deal with the Hawks. In July 2013, Mack joined the Hawks for the
2013 NBA Summer League. On February 21, 2014, he scored a then career-high 21 points in a 115–107 loss to the
Detroit Pistons. In 2013–14, he played 73 games, averaging 7.5 points, 2.2 rebounds and 1.7 assists per game. On August 22, 2014, Mack re-signed with the Hawks to a three-year, $7.3 million contract. On December 17, 2014, he scored a career-high 24 points on 6-of-6 from three-point range off the bench in a 127–98 win over the
Cleveland Cavaliers.
Utah Jazz (2016–2017) On February 18, 2016, Mack was traded to the
Utah Jazz in a three-team trade involving the Hawks and the
Chicago Bulls. The move reunited him with former Butler teammate
Gordon Hayward and former Hawks assistant
Quin Snyder. He made his debut for the Jazz on February 21, recording a season-high 16 points and six assists off the bench in a 115–111 loss to the
Portland Trail Blazers. In the Jazz's next game two days later, Mack was elevated to the starting point guard role, replacing
Raul Neto. He subsequently topped his season-high with 17 points in 32 minutes of action, as the Jazz defeated the
Houston Rockets 117–114 in overtime. On March 11, he scored a career-high 27 points in a 114–93 win over the Washington Wizards. On December 8, 2016, Mack scored a season-high 19 points in a 106–99 loss to the
Golden State Warriors.
Orlando Magic (2017–2018) On July 9, 2017, Mack signed with the
Orlando Magic. In the
2017-18 NBA season, Mack led the Orlando Magic in assists, with 3.9 per game. On June 25, 2018, he was waived by the Magic.
Memphis Grizzlies (2018–2019) On August 7, 2018, Mack signed with the
Memphis Grizzlies. On February 7, 2019, Mack was traded to the
Atlanta Hawks in exchange for
Tyler Dorsey. He was waived by the Hawks the following day.
Charlotte Hornets (2019) On February 10, 2019, Mack was claimed off waivers by the
Charlotte Hornets.
Olimpia Milano (2019–2020) On July 25, 2019, Mack signed a two-year deal with
Olimpia Milano of the Italian
Lega Basket Serie A and the
EuroLeague. He appeared in 19 games for Milano, averaging 5.8 points, 2.4 rebounds, and 2.4 assists in 18 minutes per game.
Hapoel Jerusalem (2020) On January 16, 2020, Mack parted ways with Milano to join
Hapoel Jerusalem of the
Israeli Premier League for the rest of the season.
Panathinaikos (2020–2021) On November 7, 2020, Mack signed a two-month deal with European powerhouse
Panathinaikos of the
Greek Basket League and the
EuroLeague. His contract was subsequently renewed for the rest of the 2020–2021 season. On June 6, 2021, Mack parted ways with the Greek club amidst the
domestic competition finals against
Lavrio in order to attend to personal matters overseas. In 23
GBL and 21
EuroLeague games with the Greens, Mack averaged 6.5 points, 2 rebounds, and 4 assists. == Broadcasting ==