After going undrafted in the 2017 NBA draft, Briscoe joined the Philadelphia 76ers for the 2017 NBA Summer League. In six games for the 76ers, he averaged 5.5 points and 2.2 assists per game. On September 14, 2017, he signed a training camp contract with the Portland Trail Blazers. He was waived by the Trail Blazers on October 13, 2017 after appearing in six preseason games. Briscoe signed with Estonian club &lt;a href="BC%20Kalev"&gt;Kalev/Cramo&lt;/a&gt;. On February 16, 2018 Briscoe scored 50 points as he took home MVP honors at the Estonia/Latvia All Star Game. On June 9, 2018, Briscoe won the VTB United League Young Player of the Year award, given to the league's best player under age 23. In the 2017–18 season Briscoe averaged 18.5 points, 3.4 rebounds, 4.2 assists, and 1.6 steals in 26.7 minutes per game.