[3] Under the guidance of renowned coach Stephen Francis, Jackson switched to the 100 m and 200 m sprints for the 2021 season, running personal bests of 10.77 s and 21.82 s respectively at the Jamaica Olympic Trials in Kingston.

She came third in the 100 m at the delayed 2020 Tokyo Olympics with even better career best of 10.76 s, just behind fellow country woman Shelly-Ann Fraser-Pryce who clocked 10.74 s. The Jamaicans swept the medal stand in the event for the second time in history as Elaine Thompson-Herah took the gold medal in 10.61 s.[5] In the 200 m, she failed to advance out of the heats after she slowed down before the finish line and was passed by Dalia Kaddari for the third automatic advancement spot by four one-thousandths of a second; her time of 23.26 s was not fast enough to earn one of the advancement-by-time places.

[6][7] Jackson continued to impress in the shorter sprints throughout the 2022 season winning three medals at the World Championships in Eugene, Oregon.

At the Jamaican trials, she won the sprint double, clocking 10.77 s in the 100 m and 21.55 s in the 200 m; her time at the latter elevated her to third on the respective world all-time list.

[3] In the 4 x 100 m relay final, Jackson ran a spectacular split of 9.72 s on the anchor leg, but wasn't able to pass the American sprinter Twanisha Terry.

Consequently, she and the Jamaican team consisting of Kemba Nelson, Elaine Thompson-Herah and Shelly-Ann Fraser-Pryce earned the silver medal in a season's best of 41.18 s, the sixth fastest time in history.

[3][11] Before the World Championships, Jackson had set a 100 m personal best of 10.65 s at the Jamaican trials, moving her up to joint fifth on the all-time top list.