Okello began playing soccer at age six with the North York Hearts SC.[1] He later played for Mooredale SC before joining the Toronto FC Academy in 2013.[2] On August 20, 2017, he was part of the U17 side that beat Juventus U17 to capture the inaugural International Youth Soccer Cup.[3]
Club career
Toronto FC
In 2016, he appeared in one match for Toronto FC III in League1 Ontario.[4] In 2017, he scored one goal in 13 appearances[5] and made a further two appearances in 2018.[6]
In September 2017, Okello signed his first professional contract with Toronto FC II in the USL.[2][7] On October 6, 2017, he made his professional debut against Bethlehem Steel FC.[8] Following the conclusion of USL season, Okello was invited to train with the U19 team of VfL Wolfsburg.[9] On January 10, 2018, he played a full 90 minutes for their U19 side in a 2–1 victory over Hallescher FC where he scored the equalizing goal in the 88th minute[10] He then returned to Toronto, to join the Toronto FC first team's 2018 pre-season training camp.[11] It was later reported that VfL Wolfsburg had made three separate transfer bids to sign Okello, which would see his club receive a six figure transfer fee in addition to appearance fees and sell on percentage fee.[12]
In January 2019, Okello signed a first-team contract with Toronto FC in Major League Soccer.[13][14] He made his first-team debut for Toronto on August 14 against Ottawa Fury FC in the second leg of their 2019 Canadian Championship semi-final series.[15] He made his MLS debut on July 21, 2020, against the New England Revolution.[16][17] He was loaned to the second team for some matches in 2021.[18] He scored his first goal for TFCII on June 30, converting a penalty kick against Tormenta FC.[19] Upon completion of the 2021 season, Okello's option for the 2022 season would be picked up by Toronto.[20] After appearing in four of the first five matches of the 2022 season, Okello suffered an injury that kept him out of action for five months.[21] After the end of the 2022 season, he departed the club, upon the expiry of his contract.[22]
Loan to HB Køge
On September 25, 2020, Okello was sent out on loan to Danish 1st Division club HB Køge, the same club that his teammate Rocco Romeo was also on loan with.[23] On September 30, he made his debut for Køge, coming on as a second-half substitute and scored a goal from 35 metres out.[24][25]
Okello made his debut in the Canadian youth system attending a camp in September 2016 with the Canada U17 team.[1] He was named to the roster for the 2017 CONCACAF U-17 Championship, where he made his international debut on April 22, 2017 against Costa Rica U17.[1]