An AP and WBCA All-American,[1][2] Sims was born in Irving, Texas and graduated from MacArthur High School.

She was rated the number one point guard in the class of 2010, earned the WBCA/State Farm National High School Player of the Year award and had her jersey retired.

In her sophomore season, Sims earned team Co-MVP honors with teammate Brittney Griner, scored in double-digits in 30 of 40 games and won an NCAA Championship after Baylor defeated Notre Dame 80–69 to win their second title in school history after a perfect 40–0 record during the season, making it the first time ever in college basketball history that a team has achieved such a record, they defeated Notre Dame 80–69 in the championship game to win their second title in school history.

In her rookie season, Sims immediately entered the starting line-up for the Shock at the shooting guard position.

The Shock would make the playoffs with the number 3 seed in the Western Conference, posting an 18–16 record, but were eliminated in a two-game sweep by the Phoenix Mercury in the first round.

[9] She initially came off the bench, but would be inserted into the starting lineup at the shooting guard spot after Essence Carson suffered a right elbow sprain.

On August 24, 2017, Sims scored a season-high 28 points along with eight assists and six rebounds as a starter in an 82–67 victory over the Phoenix Mercury.

[10] The Sparks would finish with a 26–8 record as the number 2 seed in the league with a double-bye to the semi-finals, following last season's new playoff format.

Sims tied her playoff career-high of 22 points in Game 3, with the Sparks winning 89–87 to clinch their second consecutive berth to the Finals.

[11] On May 20, 2018, in the Sparks' season opener, Sims scored a season-high 21 points in a 77–76 victory over the Minnesota Lynx.

[14] Sims would be the starting point guard for the Lynx, her role enabled her to average a new career-high in assists.

Sims was suspended for the first two regular season games without pay stemming from a DUI charge in October 2019 to which she pleaded guilty.

[15] She would end up missing more time after giving birth to her first child in April and eventually made her return in August.

In the second round elimination game, the Lynx edged out the Phoenix Mercury 80–79, advancing the franchise back to the semi-finals.

[33] Sims was selected to be a member of the team representing the US at the 2013 Summer Universiade held in Kazan, Russia.

Crystal Bradford scored a basket with 134 seconds left ant he game to secure a 79–78 victory.