Theodoropoulous received the
Andreas and Iphigeneia Syngros Silver Medal for her piano skill in 1910 and was appointed to teach
music history and
pianoforte at the conservatoire. During this early period, seeking different methods to express herself, Theodoropoulous wrote at least two plays. One, entitled Chance or will () (1906), which was not performed as it was semi-autobiographical, and Sparks dying out (), which was performed in 1912 by
Marika Kotopouli. In 1911, she became involved with establishing the Sunday School for Working Women () (KSE), an organization which demanded for the first time that education for women was a right. During the
Balkan War (1912–13), she returned to volunteering as a nurse and was
honored for her participation with the Medal of the Hellenic Red Cross, the Queen Olga Medal, the Medal of the Balkan War and the Medal of the Greco-Bulgarian War. In 1918, Theodoropoulous was one of the founders of Sister of the Soldier (), an association created to address social issues caused by war and give women an active means to participate civically. The organization aimed to
enfranchise women and give them civic and political rights. The following year, she left the Athens Conservatoire and began teaching at the
Hellenic Conservatory. In 1920, Theodoropoulous, along with , ,
Maria Svolou, and other feminists, established the
League for Woman’s Rights () and sought an association with the
International Woman Suffrage Alliance (IWSA) to further their demands for equality. From the beginning, the organization was one of the most dynamic of the Greek feminist organizations. In 1920, she presented a resolution to the
Greek government on behalf of the association demanding that the legal inequalities barring women from voting be addressed. The following year, she became president of the League and would remain so until 1958, except during the
war when the organization was banned. The KSE ceased operations in 1922 and Theodoropoulous turned her attention toward the Supervision Service and the National Shelter (), which were both organizations aimed at helping refugees from the
Greco-Turkish War. At the end of the conflict, Greece was flooded with refugees and the League's Supervision Service provided volunteers at fifty settlements to provide aid. The National Shelter was an orphanage, which could house up to 85 girls. In 1923, Theodoropoulous launched the League’s journal
Woman’s Struggle () and participated in the IWSA’s 9th conference held in Rome. She became a board member of the IWSA and served until 1935 and from the contacts she made at the conference, established the
Little Entente of Women () (LEW) which met in Bucharest later that year. At that conference, Theodoropoulous honored with the
King Alexander I of Yugoslavia Medal for her work for peace. LEW was made of up feminists from Czechoslovakia, Greece, Poland, Romania and Yugoslavia and she helped co-organized their annual conferences. Theodoropoulous served as the president of the Greek LEW from 1925 to 1927, following the presidency of
Alexandrina Cantacuzino. She was extremely active in this period with international conferences and gained some success at home, when in 1930 educated Greek women were allowed the right to elect local officials. ==Later career==