Garrett earned All-Big 12 second team honors and USBWA All-District VI accolades while averaging 17.3 points, 6.1 assists and 1.7 steals per game.

[6][7] On November 5, 2012, Garrett made his NBA debut recording 2 points, 2 assists and 1 steal in a 99–124 loss to the Miami Heat.

[13] On July 10, 2014, Garrett was traded to the Toronto Raptors in exchange for Steve Novak and a 2017 second round pick.

[21] In July 2015, Garrett joined the Los Angeles Clippers for the 2015 NBA Summer League.

[23] In 32 starts he averaged 19.0 points (3rd in the league), 6.2 assists (2nd), and 1.4 steals per game, with an .826 free throw percentage.

[27] On February 18, 2018, Garrett won the 2018 edition of the Italian Basketball Cup with Fiat Torino by beating Germani Basket Brescia 69–67 in the Finals.

Meanwhile, he also personally averaged 18.4 points, 2.8 rebounds, 6.1 assists and 0.7 steals per contest, while shooting 43.5% from beyond the arc, in the team's EuroCup games.

After a long hiatus due to personal injuries and the COVID-19 pandemic, Garrett signed with EuroCup club Promitheas Patras of the Greek Basket League, on July 31, 2020.

In 29 starts he averaged 15.6 points (10th in the league), 4.8 assists (9th), and 1.5 steals (10th) per game, with an .859 free throw percentage.

[24] In the summer of 2022, Garrett signed with Ironi Kiryat Ata of the Israeli Basketball Premier League.

His father played five seasons in the NBA for the Los Angeles Lakers, Buffalo Braves, New York Knicks and Milwaukee Bucks, averaging 10.3 points per game.