He played college basketball for the Wichita State Shockers and was selected 26th overall by the Philadelphia 76ers in the 2018 NBA draft.

He has also played for the Los Angeles Clippers, Brooklyn Nets, Phoenix Suns, and Washington Wizards.

[3] Shamet's uncle Tyler was a positive influence in his life growing up, and his extended family also provided support in his development.

[10] Shamet led the AAC in several categories, including assists per game, true shooting percentage, and offensive box plus/minus.

[13] In the 2018 preseason, Shamet averaged 8.8 points per game, with an 18-point performance in a 120–114 victory over the Dallas Mavericks in China.

[14] Shamet scored a career-high 29 points off the bench on January 8, 2019, in a home victory over the Washington Wizards, including a Sixers rookie record 8 three-pointers.

[20][21] On August 6, 2021, Shamet was traded to the Phoenix Suns in exchange for Jevon Carter and the draft rights to Day'Ron Sharpe.

[23] On December 20, 2022, Shamet scored a career-high 31 points, including tying a franchise-record 9 three-pointers made in a single game alongside teammate Cameron Johnson, Aron Baynes, Channing Frye, and Quentin Richardson in a 113–110 loss to the Washington Wizards.

On May 7, 2023, Shamet scored 19 points during a 129–124 win over the Denver Nuggets during the Western Conference Semifinals.