2018 On March 17 at the
Bob Hayes Invitational in
Jacksonville, Florida, Williams broke the world age-15 record in the girls' 100 metres, winning in a time of 11.13 seconds. The previous record had been 11.17 seconds, set almost 27 years prior by
Marion Jones on 1 June 1991. Two weeks later she earned gold medals in the 100 metres, the 200 metres, and the
metres relay at the
2018 CARIFTA Games in the under-17 category, setting championship records in the 100 metres and relay. In July she became the youngest athlete ever to win both the women's 100 metres and the 200 metres at the
2018 IAAF World U20 Championships in
Tampere.
2019 At the
2019 CARIFTA Games in April, Williams again tripled in the 100 m, 200 m, and relay to win three gold medals in the under-20 category. On 1 June, Williams set a new Jamaican under-18 and under-20 record in the women's 100 metres at the JAC Open in
Jacksonville, Florida, improving on
Kiara Grant's under-20 record set the month prior by one hundredth of a second to 11.10 seconds. Grant took the record back a week later at the
NCAA Division I Championships in
Austin, Texas with a 11.04 seconds finish in the final, but less than an hour later Williams improved the record to 11.02 seconds at the Great Southwest Classic in
Albuquerque, New Mexico. Williams ran 10.94 s in the 100 m final at the Jamaican Championships on 21 June 2019, which would have set the
world under-18 best time and improved her Jamaican under-20 record. However, she tested positive for the banned diuretic
hydrochlorothiazide during the competition. While she was ruled to be not at fault and received no period of ineligibility to compete, her results from the Jamaican Championships were deleted from the records. A day later in the American Track League at the same track she ran 10.97 in the prelims, but the time was
assisted by a +2.5 m/s wind, making it ineligible for record purposes which allow no more than a +2.0 m/s wind velocity. In the final she clocked 10.98 seconds to win with only a +1.0 m/s wind, setting her second Jamaican under-20 record in two days. In June 2021, Williams placed fourth at the Jamaican National Championships with a time of 11.01 in the 100 metres, thus not qualifying for the
2020 Summer Olympics in that event. However, she competed at the Olympics as a part of the 4 × 100 metres relay team, winning the
gold medal. ==Awards and recognition==