Tadeusz Lomnicki's journey in the theatre arts began in 1945 when he enrolled in the Theatre Studio at the Stary Teatr in Krakow. The following year, he spent a season at the Teatr Slaski in Katowice, before returning to Krakow in 1947 to appear on stage at both the Teatr im. Juliusza Slowackiego and the Stary Teatr.
In 1949, Lomnicki left for Warsaw, where he signed on with the Teatr Wspolczesny. He would remain there until 1974, although he did perform occasionally at the National Theatre in Warsaw during this period. In 1951, he became a member of the Communist Party, and he also studied stage direction at the State Higher School of Theatre in Warsaw, earning a directing degree in 1956.
Lomnicki's professional trajectory continued to unfold, as he became the rector of the theatre school in Warsaw in 1970, a position he retained until 1981. In 1975, he was elected a member of the Central Committee of the Communist Party, and in 1976, his initiative led to the creation of the Teatr na Woli, which he headed until his resignation in 1981.
Around the time he left the theatre, Lomnicki handed in his Communist Party membership card, and the following year, he joined Warsaw's Teatr Polski. In 1983/84, he was an actor at the Teatr Studio in Warsaw. Throughout the 1980s and 1990s, he was not linked to any institutional theatre, instead making numerous guest appearances at a number of Warsaw theatres.
For a long time, Lomnicki had dreamed of playing the part of King Lear, and he finally succeeded in mounting a production. He approached noted translator and poet Stanislaw Baranczak to produce a new translation of the play, and then approached a number of directors about working with him on the production. Ultimately, Eugeniusz Korin agreed to direct the production at Poznan's Teatr Nowy.
Tragically, Tadeusz Lomnicki passed away on February 22, 1992, just one week before the premiere of the production.