Smith was born in North York, Ontario, but grew up in Whitby. She first played house league with the Whitby Soccer Club, before playing at the competitive level with Oshawa Kicks SC, Ajax SC, Markham FC and then North Toronto SC.[2][3] Afterwards, she joined the Ontario Regional Excel (REX) program (later renamed to the NDC Ontario),[4] before returning to North Toronto SC to train in advance of her move to college, where she committed to join the Florida State Seminoles.[5]
In 2022, Smith played for the North Toronto Nitros in League1 Ontario.[12] She made her debut on May 7 against Alliance United.[12] In her next match on May 14, she scored her first goal against Simcoe County Rovers FC.[13] She scored a brace on May 18 against Electric City FC.[14] She scored four goals in a 6–1 victory over BVB IA Waterloo on June 18.[15] After the season, she was named Young Player of the Season, Forward of the Year, and won the Golden Boot after leading the league in scoring with 18 goals, while only appearing in 11 games.[16] She was also named a league First Team All-Star and U18 All-Star in 2022.[17][18]
In July 2023, Smith signed her first professional contract and joined Portuguese club Sporting CP in the Campeonato Nacional Feminino on a three-year deal.[19][20] In her league debut, she scored and added an assist for the club.[21][22] Enjoying success in her first professional season, a season-ending poll of the league's coaches and captains voted Smith the player of the year.[23] She later received the league's juried award as best young player of the season.[24]
In July 2024, she signed with English club Liverpool in the Women's Super League.[25][26] She became the first ever woman to score for Liverpool at Anfield in a 2-1 defeat to Man City.
In late October 2019, she was called up to the Canada women's national soccer team for the first time.[28] On November 7, 2019, she became the youngest player ever to debut for the senior national team at the 15 years and 94 days old, when she replaced Jordyn Huitema in the 86th minute of a match against Brazil in the Women's International Tournament played in Chongqing, China, breaking the previous record set by Kara Lang.[2][29] In the same tournament, Smith got her second international cap in a match against New Zealand.[30] Following the appearance, she then attended a camp with the Canada U17 team.[31][32]
After being a late addition to the Canadian pre-tournament camp for the 2023 FIFA Women's World Cup, Smith was named to the final squad. At age 18, she was its youngest member.[37][38] Smith made her World Cup debut in Canada's final group stage match, as a substitute against Australia.[39][40]
Smith began 2024 being named to the Canadian squad for the 2024 CONCACAF W Gold Cup, while citing that her "biggest goal" for the year was to make the smaller eighteen-person team for the 2024 Summer Olympics in Paris.[41] She scored her first senior international goal in Canada's opening game of the Gold Cup, a 6–0 rout of El Salvador.[42] Smith was then given her first start at the senior level in the second group game, against Paraguay, and scored her second goal of the tournament.[43] She missed the quarter-final against Costa Rica while in concussion protocol.[44] Smith played thirty minutes of extra time in the semi-final versus the United States, which ultimately saw Canada ousted in the penalty shootout.[45] She received the Young Player Award at the conclusion of the tournament.[46] The Gold Cup was called Smith's "true breakout on the international stage."[45] Due to injury, she was unable to participate in the 2024 SheBelieves Cup,[47] and ultimately was not included in the Canadian Olympic roster.[48] Smith was named the 2024 Canada Soccer Young Player of the Year.[49]
^Araújo, Andreia; Sousa, Daniel (May 6, 2024). "Olivia Smith é a melhor jogadora da Liga BPI 2023/24" [Olivia Smith is the best player in the BPI League 2023/24]. ZeroZero (in Portuguese). Archived from the original on May 12, 2024. Retrieved May 11, 2024.