Morrison attended Geelong Grammar School and grew up a supporter, citing Joel Selwood and Patrick Dangerfield as players she enjoyed watching. A long-distance runner in her youth who also played tennis and soccer at school, Morrison did not take up football until her father encouraged her to attend a Geelong trial in late 2016. Although she was unavailable for the under-18 trials as they conflicted with tennis commitments, she instead attended the senior trials, where she impressed Geelong representatives by outplaying the older women. Morrison joined the Geelong Falcons, playing in the TAC Cup Girls, and represented Vic Country in the 2017 AFL Women's Under 18 Championships. Additionally, she played for local club St Mary's, kicking thirty-five goals in eight games playing as a midfielder in the under-19 AFL Barwon league. In 2018, Morrison won the TAC Cup Girls premiership with the Falcons and tied with Madison Prespakis for the leaguebest and fairest with 16 votes. She again played for Vic Country in the 2018 AFL Women's Under 18 Championships and won their most valuable player award. Morrison was named in the All-Australian side on the wing, and shared the competition's most valuable player award with Prespakis. She played four VFL Women's matches for the, including a best-on-ground performance against in the elimination final and the losing grand final against, where she was again among the best. Morrison tested at the AFL Women's draft combine, breaking records in the two-kilometre time trial and the yo-yo endurance test. She reached level 18.1 in the yo-yo test and ran the time trial in seven minutes and fourteen seconds, fifteen seconds faster than the previous record. Morrison additionally placed in the top five for the standing vertical jump, agility test and running vertical jump. In the lead-up to the draft, Morrison was widely predicted to be taken by with the first selection. Draft prospects selected a state or region they wished to play in prior to the draft; options for Victorian players included Geelong, the Melbourne metropolitan area or the entire state. Morrison opted for Geelong while Prespakis, another top prospect, nominated the metropolitan area; this improved Morrison's chances of being taken with the first selection in the draft, as Geelong held the first two selections.
AFL Women's career
Morrison was drafted by Geelong with the first selection in the 2018 AFL Women's draft. Ahead of the 2019 AFL Women's season, she polled the most votes by the AFLW captains as their predicted winner of the 2019 AFL Women's Rising Star award. Morrison made her debut in the opening round of the season against at GMHBA Stadium, where she was nominated for the AFL Women's Rising Star award after accumulating 22 disposals and eight tackles and kicking the winning behind in a best-on-ground performance. Morrison also polled the maximum ten votes in the AFLW Champion Player of the Year Award and was named in womens.afl's Team of the Week. However, she ruptured the anterior cruciate ligament in her right knee at training the following week, which required a reconstruction. After missing the rest of the 2019 season, Morrison made a successful return to football in round 1 of the 2020 season against at Fremantle Oval, kicking a goal.
