As a young girl Kathellen loved football but mainly had to play
futsal. She found opportunities for field soccer limited in her native
Baixada Santista, especially after
Santos FC's women's section was closed in 2012. Kathellen applied for an
athletic scholarship to the United States and was selected by
Monroe College of the
National Junior College Athletic Association. After two successful years with Monroe College she spent her two remaining years of college eligibility with
Louisville Cardinals and
UCF Knights, respectively, in
NCAA Division I. She subsequently received an offer from
FC Girondins de Bordeaux and joined the French
Division 1 Féminine club halfway through their
2017–18 season. In May 2018 she signed a two-year extension to her contract. After a successful
2019 FIFA Women's World Cup with Brazil, and an elite level performance against France, Kathellen was linked to many major European clubs, including newly promoted
CD Tacón, due to become Real Madrid for season 2020–21. Instead she remained with Bordeaux for a further season, then joined Italian
Serie A club
Inter Milan in August 2020. In 2024, she left Real Madrid and joined
Al-Nassr on a two-year contract, with her official debut coming on 25 of August in the
AFC Women's Champions League, which she helped her team keep a clean sheet. ==International career==