[3] Attending Hopkins High School in Minnetonka, Minnesota,[4] Coffey received Minnesota Mr. Basketball honors as a senior,[5] while earning Associated Press State Player of the Year[6] and Star Tribune Metro Player of the Year distinction.

A four-star recruit and ranked 32nd overall in ESPN’s top 100 for the class of 2016,[8] Coffey announced his decision to play college basketball at Minnesota in September 2015.

After going undrafted in the 2019 NBA draft, Coffey signed a two-way contract with the Los Angeles Clippers.

[13][14] On August 14, 2020, he scored a season-high 21 points, along with four steals, in a 107–103 overtime win over the Oklahoma City Thunder.

[18] On April 1, he logged a career-high 32 points, alongside seven assists and four steals, in a 153–119 blowout win over the Milwaukee Bucks.