Quinn attended UCLA and graduated in 2007. She was the first Bruin — men's or women's player — to total 1,700 points, 700 rebounds, and 400 assists in her collegiate career.[5] Quinn was twice named honorable mention All-American, earned first-team All-Pac-10 player honors three times, and was twice named a Pac-10 All-Tournament honoree.[5] She was named Pac-10 Player of the Week eight times (a conference record).[5] In 2006, she led the team to its first Pac-10 Tournament title and recorded 22 points in the championship game.[5]
Quinn was inducted into the UCLA Hall of Fame in 2020.[5]
Quinn was drafted by the Minnesota Lynx in the first round of the 2007 WNBA draft.[7] As a rookie she got off to a slow start before stepping into the point guard role when Lindsey Harding was injured in July, 2007. Quinn finished strong, setting a franchise record with 14 assists on August 19, the season finale. She finished the season averaging 2.8 points and 4.4 assists per game. Her 148 assists for the 2007 season, tied a club record that was held by Teresa Edwards.
Beginning in 2016, Quinn coached the girls basketball team at her high school alma mater, Bishop Montgomery High School, for four seasons. In her first season, the Lady Knights won a California Interscholastic Federation (CIF) Southern Section championship.[4]
In February 2019, after retiring from the WNBA, Quinn was hired as an assistant coach by her last team, the Seattle Storm.[10]
For the 2020 season, Storm head coach Dan Hughes was forced to sit out the season for medical reasons. Gary Kloppenburg became head coach for the season, and Quinn was promoted to associate head coach, where she concentrated on the offense, while Kloppenburg focused on the defense.[11] Seattle won the 2020 WNBA championship.
On May 30, 2021, Quinn was named Storm head coach upon Hughes' retirement from the WNBA.[12]