As a freshman, White started all 52 games and hit .318/.369/.410 with two home runs and 28 runs batted in (RBIs).[3] As a sophomore in 2016, White started all 54 games, hitting .376/.419./.535 with five home runs and 40 RBIs.[4] After the season, he played for the United States collegiate national team.[5]
Considered one of the top prospects for the 2017 Major League Baseball draft,[6][7] the Seattle Mariners selected White with the 17th overall selection.[8] After signing, he was assigned to the Everett AquaSox where he posted a .277 batting average with three home runs, 12 RBIs and a .877 OPS in 14 games.[9] In 2018, White played with the Modesto Nuts and the Tacoma Rainiers, slashing a combined .300/.371/.453 with 11 home runs and 66 RBIs in 124 games.[10] He spent 2019 with the Arkansas Travelers,[11] batting .293/.350/.488 with 18 home runs and 55 RBIs over 92 games. White was named to the 2019 All-Star Futures Game.[12]
On November 25, 2019, White signed a six-year major league contract (with three club options) with the Mariners.[13] The contract guaranteed White at least $24 million and could reach $55.5 million.[14] On July 24, 2020, White was the starting first baseman, making his MLB debut on Opening Day. He finished the season with a .176 batting average, the lowest among all qualifying hitters in the shortened 60-game season, and a .252 on base percentage, also the lowest, along with eight home runs and 26 RBIs in 54 games.[15] He won his first Gold Glove Award in 2020, manning first base.[16]
On June 22, 2021, White was placed on the 60-day injured list with a left hip flexor strain and was sent for a second opinion on the injury.[17] White elected to undergo season-ending hip surgery on July 16.[18]
On March 26, 2022, it was announced that White would undergo surgery to repair a sports hernia.[19] On April 28, White was transferred to the 60-day injured list as he continued to recover.[20]
White was optioned to Triple-A Tacoma to begin the 2023 season.[21] On April 6, 2023, it was announced that White had suffered a Grade 2 groin strain while playing with Tacoma and would miss two months of action.[22] On May 9, it was announced that White would undergo another procedure on his left hip, causing him to miss three months.[23]