[1][2][3] He began playing basketball in Sydney and participated in the annual South Sudanese Australian National Classic.
[4] His friend, Deng Adel, convinced him to play high school basketball at Victory Rock Prep in Bradenton, Florida.
[5][6] He helped Victory Rock Prep to a championship in the team's season-ending Grind Session National Tournament.
[7][9] Gak was initially ruled ineligible by the NCAA at the beginning of his rookie season, due to questions about the number of games he played at Victory Rock Prep.
[5] As a sophomore in 2017–18, Gak battled through knee soreness and swelling all season[5] and averaged 2.2 points and 2.4 rebounds in 29 games.
[13] He helped the team win the Czech League championship and averaged 13.5 points, 10.1 rebounds, 1.9 assists and 1.7 blocks per game.
[14] On 6 July 2022, Gak signed with the Brisbane Bullets of the National Basketball League (NBL) for the 2022–23 season.
[23] On 18 April 2024, Gak signed a two-year deal with the Tasmania JackJumpers, with the second year containing a club option.