[2] Teodoroiu was born in the village of Vădeni (now part of Târgu Jiu), in the historical region of Oltenia, in the family of Elena and Vasile Toderoiu, both farmers.

[2] Before she could start her preparation for a teaching certificate, the Kingdom of Romania entered World War I in August 1916, on the side of the Allies.

14 October] 1916 Teodoroiu joined the civilians and the reserve soldiers fighting to repulse the attack of a Bavarian company of the 9th German Army at the bridge over the Jiu River, in front of Târgu-Jiu.

[1][4] Wishing to avenge her brother's death, Teodoroiu asked Colonel Obogeanu to allow her to join the 18th Infantry Regiment as a volunteer.

3/4 November] 1916, but managed to escape with light wounds by killing the German soldier who was guarding her with a gun she had concealed in her uniform.

4 August], the 43/59 Regiment, part of the reserve of the 1st Army led by General Eremia Grigorescu, prepared to join the upcoming offensive.

5 August] the regiment left Vaslui for Tecuci, crossed the Siret and camped in the Malta Seacă forest, close to the frontline.

17 August], the commander of the 11th Division, General Ernest Broșteanu, kindly asked her to stay at the mobile hospital behind the front, but Second Lieutenant Teodoroiu strongly refused him, requesting to be allowed to join her platoon in the upcoming battle.

1 issued the next day by Colonel Constantin Pomponiu, the commanding officer of the 43/59 Regiment, her last words before getting hit by machine gun fire and dying shortly afterwards were: "Forward, men, don't give up, I'm still with you!"

Initially buried close to the front, in Fitioneşti,[1] her remains were interred in June 1921 in a crypt in the city center of Târgu Jiu.

[1] In 1937, by Royal Decree, the Girls' High School in Târgu-Jiu was given her name (currently the National College "Ecaterina Teodoroiu").

[21] Kathryn J. Atwood dedicated a chapter to Ecaterina Teodoriu in her work "Women Heroes of World War I: 16 Remarkable Resisters, Soldiers, Spies, and Medics".

[23] In November 2021 the National Bank of Romania announced that the 20 lei banknote bearing Ecaterina Teodoroiu's portrait would be issued on 1 December 2021.