Sandrine Mauron

Gaillard started her professional career at FC Yverdon Féminin, a team playing in the Nationalliga A, the highest-level league competition for women's football clubs in Switzerland. In 2014, Gaillard moved to Swiss traditional club FC Zürich. With the team, she was twice national champions and won two national cups. She also played in four consecutive editions of the UEFA Champions League. On 29 June 2025, Gaillard signed a contract with USL Super League champions Tampa Bay Sun FC. She made 24 appearances and racked up 1,148 minutes for the Sun before departing from the club after one season. On 7 July 2026, Gillard returned to FC Yverdon Féminin on a one-year contract.

Youth

Gaillard was part of the squad that represented Switzerland at 2013 UEFA Women's Under-17 Championship qualification when she played six matches and scored two goals. With the U19 team, Gaillard played in the 2015 UEFA Women's Under-19 Championship qualification and the 2016 UEFA Women's Under-19 Championship qualification. In the 2016 edition, Switzerland was able to qualify for the final tournament reaching the semi-finals when they were defeated by France, that would eventually win the tournament.

Senior

In 2015, Gaillard was called for Swiss Senior Team for the first time. In 2016, she made her debut for the team. On 23 October 2016, in a friendly match against United States, she scored her first international goal. On 3 July 2017 Gaillard was called by coach Martina Voss-Tecklenburg to represent Switzerland at the UEFA Women's Euro 2017, but she didn't play any matches as Switzerland was eliminated in the tournament's group stage. In 2022, she took part in the Euros in England with another defeat in the group stage and a year later she was selected as part of the final squad that went to Australia and New Zealand to play in the 2023 World Cup. Switzerland made it to the last 16, where they lost to the eventual champion Spain. On 23 June 2025, Gaillard was called up to the Switzerland squad for the UEFA Women's Euro 2025.

Yverdon

Swiss Cup Winner: 2010, 2011 FC Zurich

Swiss Champion: 2015, 2016, 2018, 2019 Swiss Cup Winner: 2015, 2016, 2018, 2019 Servette FC Chênois Féminin

Swiss Champion: 2024 Swiss Cup winner: 2023, 2024 Personal awards

Swiss All Star Team: 2015, 2016, 2017