Siemsen attended Oxford Falls Grammar School.[3] She played junior football for BTH Raiders.[4] Siemsen was selected for the Australian School Girls Squad and represented Football NSW at the National Training Centre (NTC) Challenge. At age 16, she was named Football NSW NPL Women's Player of the Year.[5]
Club career
Sydney FC
Siemsen made her debut for Sydney FC during the 2016–17 season at the age of 16.[6] Sydney finished in third place during the regular season with a 7–4–1 record and advanced to the semi-finals where they were eliminated by Perth Glory.[7] Siemsen finished her first season with six goals, ranking as the club's top scorer.[2] She was named the league's Young Footballer of the Year in May 2017.[8][9][10] She was named the 2016 Junior Sports Star by the Manly Daily.[11]
Returning to Sydney for the 2017–18 season, Siemsen scored the game-winning goal coming off the bench as a substitute against former champions Melbourne City on 18 November.[12] Siemsen finished off the 2017–18 season with 4 goals and a grand final finish with her Sydney FC team.
California Storm
In April 2018, Siemsen joined Women's Premier Soccer League (WPSL) side California Storm on a short-term contract.[13][14] In her first game as a Storm player, she scored a brace in a 3–2 loss to Fresno FC. She was named WPSL West Region Player of the Week in Week 3 after tallying two goals and one assist on the road against Primero de Mayo.[15] On 23 June, she scored a hat-trick in a 4–1 victory against the MVLA Wolves. She finished the season with 9 goals and 5 assists in 8 appearances.[16]
In the 2019 off-season, Siemsen returned to Sydney FC.[18] She marked he return during the first match of the 2019–20 season by scoring a brace in a 3–0 victory over Melbourne Victory.[19] Following that performance and her performance in Sydney FC's 1–0 victory over Adelaide United the following week, she was named the Player of the Month for November.[20] Siemsen scored seven goals during the season and won the W-League Golden Boot in a four-way tie with foreign players Morgan Andrews, Natasha Dowie, and Kristen Hamilton.[21] In August 2020, Siemsen re-signed with Sydney FC ahead of the 2020–21 W-League season.[22] Over the season, Siemsen scored another seven goals, winning Sydney FC's Golden Boot for the third time, and in August 2021 re-signed with the club for the 2021–22 A-League Women season.[23]
AIK
In March 2022, Siemsen joined a European club for the first time, signing with Swedish club AIK.[24]
Sydney FC
In November 2022, after the 2022–23 A-League Women had already started, Siemsen returned to Sydney FC following the conclusion of the 2022 Damallsvenskan.[25] Over the course of a month, Siemsen scored two goals in four months, after which she transferred to a European club on a domestic record transfer fee.[26]
Leicester City
A couple of weeks after Sydney FC announced her departure, it was revealed that Siemsen had signed with English Women's Super League club Leicester City.[27]
^"Kristen Hamilton takes out Julie Dolan Medal". W-League. 23 July 2019. Archived from the original on 5 May 2021. There was a four-way tie for the Westfield W-League Golden Boot Award with Morgan Andrews (Perth Glory), Kristen Hamilton (Western Sydney Wanderers FC) Remy Siemsen (Sydney FC) and Natasha Dowie who all scored seven (7) goals