[19] On March 29, 2004, Parker won the slam dunk contest at McDonald's All-American Game, becoming the first woman to win the event and beating the likes of Josh Smith and J. R.

[20] In August 2004, Parker led the undefeated USA Junior World Championship team to a gold medal with 16.6 points and 8.8 rebounds per game.

[citation needed] She wears the number 3 on her jersey to honor former NBA player Allen Iverson who encouraged her during her high school career.

On February 17, 2005, Tennessee announced Parker would redshirt her first season due to a knee injury she had suffered in a summer league game.

However, in the NCAA tournament regional finals against North Carolina, Parker got in early foul trouble and was out of the game for much of the first half.

In a January 28, 2007, away game against Alabama, in her sophomore season, Parker became the fastest player in Lady Vols history to score 1,000 career points.

On April 8, 2008, despite having suffered a dislocated shoulder in the regional final, Parker led the Lady Vols to their second straight NCAA women's title, the eighth championship for Tennessee and the last for legendary coach Pat Summitt.

[26] While at Tennessee, she compiled a record of 100 wins and 10 losses and averaged 19.4 points, 8.8 rebounds, 2.6 assists, 1.9 steals, and 2.4 blocks per game.

Parker was selected as the first pick in the 2008 WNBA draft by the Los Angeles Sparks on April 9, 2008, one day after winning the NCAA title.

[32] In August 2008, the WNBA suspended play for a couple of weeks to allow their players to join the national teams at the 2008 Summer Olympics.

By this time, the Sparks had acquired Tina Thompson and Betty Lennox to help carry the team during Parker's absence.

Parker helped the Sparks get to the Western Conference Finals, but lost in three games to the eventual champions, the Phoenix Mercury.

During the seventh game, with 5:56 left in the third quarter, Parker went down after grabbing a defensive rebound and making brief contact with Quanitra Hollingsworth.

[37] Six weeks later, she returned and played the remainder of the season, but the Sparks were eliminated from playoff contention with a disappointing 15–19 record.

Parker became the fifth player to earn multiple WNBA MVP awards, joining Lisa Leslie (3), Sheryl Swoopes (3), Lauren Jackson (3) and Cynthia Cooper (2).

Despite major uncertainty, a month later the team was purchased by an investment group including Magic Johnson, with promises of bringing a championship to Los Angeles.

However, in late June, Parker's college coach and mentor, Pat Summitt, died at the age of 64 from Alzheimer's disease.

That night, against the Dallas Wings, Parker had an incredible performance in the second half, finishing the game with 31 points, and had her season high of rebounding with 13, guiding her team to a victory.

For Game 3, in Los Angeles, Parker put up her best performance of the finals thus far, contributing 24 points, 9 rebounds, and 2 assists to help the Sparks take a 2–1 series lead, with a dominant 92–75 win.

[49] In the second-round elimination game, the Sparks lost 96–64 to the Washington Mystics, ending their run of two consecutive finals appearances.

[50] Parker made her season debut on June 18, 2019, she scored 3 points on 1-of-9 shooting from the field in an 81–52 loss to the Washington Mystics.

[54] In the 2020 season, which was shortened and took place in a "bubble" at IMG Academy due to the COVID-19 pandemic, Parker started all 22 games for the Sparks.

[55] The Sparks earned the third-seed and a first-round bye in the playoffs, but lost a single-elimination game to the seventh-seeded Connecticut Sun in the second round.

Parker stated "Chicago is where my family raised me; where I first learned the game of basketball; and where I first fell in love with this orange ball.....I am excited to continue the next chapter of my career where it all began.

They won two single elimination games, followed by an upset of the Connecticut Sun in the semifinals, before beating the Phoenix Mercury to win the 2021 WNBA Finals.

She captured her third championship when the Las Vegas Aces won the 2023 WNBA Finals against the New York Liberty, taking the series 3–1.

[65][13] Parker was a member of the USA Women's U18 team which won the gold medal at the FIBA Americas Championship in Mayagüez, Puerto Rico.

[70] During each WNBA off-season from 2010 to 2015, Parker played for UMMC Ekaterinburg of the Russian League, winning five consecutive championships with the team.

During the 2015-16 WNBA off-season, Parker signed with the Guangdong Dolphins in January 2016, to replace Yelena Leuchanka during the WCBA playoffs.

In October 2020, Parker and her daughter became part of the ownership group of Angel City FC, a Los Angeles–based team in the National Women's Soccer League that began competing in 2022.