Diggins-Smith was a four-year varsity basketball letter winner at Washington High School in South Bend, where the Panthers had a combined record of 102–7.

On November 15, 2009, Diggins-Smith made her collegiate debut for Notre Dame, recording 14 points, eight rebounds, five assists and four steals in a 102–57 win over Arkansas-Pine Bluff.

On March 23, Diggins-Smith recorded 31 points, six assists, and seven steals in an 84–66 win over 10th-seeded Vermont in the second round of the 2010 NCAA tournament.

Diggins-Smith became the second Notre Dame women's basketball player to reach the 1,000-point milestone before the end of her sophomore season.

[7] She scored then season-high 24 points in a 73–59 win over fourth-ranked Tennessee in the Elite Eight to help Notre Dame reach its 3rd Final Four ever.

[9][10] In a 76–70 loss to Texas A&M Aggies at the national championship game, Diggins-Smith posted 23 points, 3 rebounds, 3 assists, 4 steals, and was named to the Final Four All-Tournament Team.

As the Associated Press reported, "Diggins, fighting back tears, said the Irish couldn't handle A&M's pressure.

On March 27, at the Elite Eight of the NCAA Tournament, Diggins-Smith recorded the first triple-double in Notre Dame postseason history with 22 points, 10 rebounds and 11 assists against Maryland.

[13] In their next game against UConn, she scored 19 points en route to earning their second straight championship appearance.

In her final season at Notre Dame, Diggins-Smith posted career-high 33 points and five assists in a 77–67 victory over Tennessee.

Diggins-Smith scored a game-high 27 points in an 87–76 win over second-seeded Duke in the Elite Eight to help Notre Dame reach its 3rd straight Final Four.

At the Final Four, Notre Dame was defeated by Big East rival UConn, 83–65, and finished the season with a 35–2 record.

She finished her career ranking first in points, steals, free throws made, free throws attempted, games started, minutes played, double-figure scoring games and triple-doubles, and second in school history for career assists, field goals made, field goals attempted and games played In the 2013 WNBA draft, Diggins-Smith was drafted 3rd overall by the Tulsa Shock.

In a regular season game loss to the San Antonio Stars, Diggins-Smith scored a career-high 34 points.

She ranked second in league in scoring with 20.1 points per game, fourth in assists with 5.0 and tenth in steals with 1.5.

Diggins-Smith finished off the season averaging 18.5 ppg as well as a career-high in assists and rebounds, helping the Wings reach the playoffs as the number 7 seed in the league.

She had also mentioned that she had taken time away from basketball due to postpartum depression and expressed her displeasure with the Dallas Wings organization for their lack of support during her absence.

Diggins-Smith made her return on July 25, 2020, scoring 14 points along with 6 assists in a 99–76 loss to the Las Vegas Aces.

On August 29, 2024, it was announced that Diggins-Smith would appear and play in the inaugural season of Unrivaled, a new women's 3x3 basketball league founded by Napheesa Collier and Breanna Stewart.

[31] Diggins-Smith was a member of the USA Women's U18 National Team, starting all five games at the 2008 FIBA U18 Americas Championship in Buenos Aires, Argentina.

In the tournament, she ranked among the top 5 in scoring (1st), field goal percentage (7th), assists (1st), steals (1st) and assist-to-turnover ratio (1st).

Diggins-Smith played on the 2009 USA U19 World Championship Team that posted an 8–1 record in Bangkok, Thailand, and brought home the gold medal.

[35] Stats current through end of 2024 season Diggins-Smith has become an advocate against childhood obesity, a guest interviewer for ESPN, and a model for Nike.

[38] Starting with the 2020-21 NBA season, Diggins Smith has also been a guest broadcast team member for the Phoenix Suns.

[38] In June 2016, Diggins got engaged to her longtime boyfriend Daniel Smith who is a former Clay High School and Notre Dame wide receiver.