Ustby was raised in Rochester, Minnesota, the daughter of Todd and Lisa Ustby, and has three older brothers.[1] She began playing basketball in second grade after having gone to her brothers' practices.[2] She attended Lourdes High School, where was named all-state three times and set school records in career points (2,560) and rebounds (1,287). In her senior year, she was nominated for Minnesota Miss Basketball and the McDonald's All-American Game.[1] She starred in two other high school sports: she set the school softball record for career stolen bases and led the team to the state championship as a junior, and she led the school soccer team in scoring as a senior with 14 goals.[1] She was a three-star recruit when she committed to the University of North Carolina. Head coach Courtney Banghart said she was "totally underrated, but I saw a high-motor, competitive and versatile athlete who had incredible footwork".[2] Ustby's parents moved to Durham, North Carolina, to be able to watch their daughter play.[3]
College career
Freshman season (2020–21)
Ustby debuted for the North Carolina Tar Heels on November 25, 2020, scoring 13 points in a 90–61 win over Radford.[4] She recorded her first double-double with 15 points and 11 rebounds off the bench in a 95–70 win over High Point on November 29. She made her first start on December 17 in a 92–68 win over Syracuse, after which she held a starting position for the rest of her career.[1] She shot 4-for-4 from three and posted 20 points and 12 rebounds in a 76–69 win over NC State on February 7, 2021.[1][5] She led the team in scoring with a career-high 23 points in an 82–71 loss to Wake Forest in the ACC tournament second round on March 4.[6] She scored 7 points and grabbed 5 rebounds for No. 10–seeded North Carolina in a 80–71 loss to No. 7 Alabama in the first round of the NCAA tournament.[1] Ustby played a team high in minutes in her freshman 2020–21 season, averaging 9.9 points and 5.7 rebounds per game.[2]
Sophomore season (2021–22)
Ustby tied her career high with 23 points and grabbed 12 rebounds in a 72–59 win over VCU in the Bahamas on November 26, 2021. She scored 12 points with 12 rebounds for No. 5 seed North Carolina in a 63–45 win over No. 4 Arizona in the second round of the NCAA tournament. In the next round, she scored only 4 points with 7 rebounds in a 61–69 loss to eventual champions No. 1 South Carolina. She averaged 12.9 points and a team-high 8.6 rebounds per game in her sophomore 2021–22 season, earning second-team All-ACC honors. Her season total of 13 double-doubles was the second most in the ACC.[1]
Junior season (2022–23)
Ustby grabbed a career-high 18 rebounds and scored 9 points in a 56–47 win over NC State on January 15, 2023.[7] On March 18, she scored her 1000th career point for No. 6 seed North Carolina in a 61–59 win over No. 11 St. John's in the first round of the NCAA tournament.[8] In the second round, she scored 16 points with 9 rebounds in a 71–69 loss to No. 3 Ohio State.[1][9] She averaged 13.2 points and a team-high 8.3 rebounds per game in her junior 2022–23 season, earning first-team All-ACC honors.[1]
Senior season (2023–24)
Ustby held a three-day girls' basketball camp in her hometown of Rochester, Minnesota, before the 2023–24 season, a year when she became one of the team's captains.[1][10] On January 4, 2024, she became the first player in program history to record a triple-double when she posted 16 points, 16 rebounds, and 10 assists in a 75–51 win over Syracuse.[11] On February 18, she set a new career high with 25 points and added 10 rebounds in a 58–50 win over Wake Forest.[12] She scored 16 points and grabbed a career-high 17 rebounds for No. 8 seed North Carolina in a 59–56 win over No. 9 Michigan State in the first round of the NCAA tournament.[1][13] In the second round, she shot 4-for-16 yet was her team's top scorer with 12 points in an 88–41 blowout loss to eventual champions No. 1 South Carolina.[1][14] She averaged 12.5 points, a team-high 9.5 rebounds, and a team-high 3.6 assists in her senior 2023–24 season, earning second-team All-ACC honors.[1][15] After the season, she announced that she would return to North Carolina for a fifth and final year. She was part of the last college class granted an extra year of eligibility due to the COVID-19 pandemic.[16]
Fifth year (2024–24)
Ustby captains the Tar Heels as the only non-transfer graduate student on the team in the 2024–25 season.[17]