Olakau'atu played junior rugby league with Berala Bears and Wentworthville Magpies. He later tried out for the Parramatta SG Ball and Harold Matthews sides but was unsuccessful. Olakau'atu then was signed by Manly and played for the club in their 2017 Holden Cup premiership winning side against Parramatta.[3]
He made five appearances for Manly in the 2020 NRL season as the club missed out on the finals finishing 13th on the table.[7]
2021
In round 14 of the 2021 NRL season, he scored two tries for Manly in a 50-18 victory over North Queensland.[8]
He played 21 games for Manly in the 2021 NRL season including the club's preliminary final loss against South Sydney.[9]
2022
Olakau'atu was one of seven players involved in the Manly pride jersey player boycott.[10]
He made a total of 21 appearances for Manly in the 2022 NRL season scoring ten tries. Manly would finish the season in 11th place and missed out on the finals.[11]
2023
In round 3 of the 2023 NRL season, he scored two tries including the winner in Manly's 34-30 victory over Parramatta.[12]
In round 5, he scored a try and was later sent to the sin bin during Manly's 32-32 draw with Newcastle.[13]
He played a total of 24 matches for Manly in the 2023 NRL season and scored ten tries as the club finished 12th on the table and missed the finals.[14]
2024
On 26 May, Olakau'atu was selected by New South Wales ahead of the 2024 State of Origin series.[15]
Olakau'atu played 21 matches for Manly in the 2024 NRL season as they finished 7th on the table and qualified for the finals. Manly would be eliminated in the second week of the finals by the Sydney Roosters.[16]