[2] Kirs began his career at ages sixteen and seventeen appearing as an uncredited extra in crowd scenes in two Estonian feature films in 2004 and 2005: Sigade revolutsioon and Malev.
The film focused on rampant bullying which leads two teens (played by Kirs and actor Pärt Uusberg) to plan and commit a school shooting.
[5] In 2023, Kirs appeared in the role of Kaltsakas Vallo in the Ain Mäeots directed historical feature film comedy Kuulsuse narrid, based on the 1892 story of the same name by Eduard Bornhöhe.
[12] As an actor, he has appeared in productions of works by such authors, playwrights and lyricists as Viktor Pelevin, Anthony Drewe and George Stiles, Tõnu Õnnepalu, Carlo Goldoni, Tom Stoppard, Gianni Rodari, and Martin Algus.
As a director, he has overseen and orchestrated the mounting of a theatre productions of works by Mati Unt, Thorbjørn Egner, André Gide, Fyodor Dostoyevsky, A. H. Tammsaare, Carlo Goldoni, John Steinbeck, Urmas Lennuk, and others.