After getting her start in the Aleppo's theatre scene, Debsi's career began in earnest after moving to the Syrian capital, Damascus, where she took part in theatre festivals before she found regional fame in television.
Debsi began acting in films from 1963 and joined the Syrian Order of Artists in 1968.
Thanaa Debsi participated with her sister, Tharaa Debsi, in the performances that the People's Theater Troupe presented on the stage of the National Library Theater in Aleppo.
Her artistic journey was rich in dozens of theatrical, cinematic and television works that spanned more than half a century. She starred in many famous Syrian series during her career including Banat Aleila, Al Wahemoon, Qaws Quzah, and Zaman Al'ar.
Defined by a fierce presence, Debsi's television work often found her taking on roles of strong and vulnerable characters.