The fight for sense was demonstrated in another role played by Kościukiewicz, this time in Paweł Sala's Mother Teresa of Cats (2010) in which he also played a young man who cannot accept the reality aaround him. In contrast to Janek from All That I Love, Artur from Mother Theresa of Cats does not grow up or mature but sinks into madness which leads to an inevitable tragedy. The film tells a story of two brothers who murder their own mother. Commenting on his award-winning role at the Karlovy Vary Festival, Kościukiewicz said to Łukasz Maciejewski:
While working on the role, I passionately returned to Dostoyevsky and his Raskolnikov as a model of a certain attitude. Neurosis, psychosis, egocentrism, complexes. Różewicz in A Story about Old Women wrote: 'I like old women, ugly women, evil women - they are the salt of the earth.' I fully agree. Youth, beauty, sincerity - these often lead to the chaos of self-deception. In Artur everything intermingles and mixes up; one feature disturbs the other. To grab an axe, one impulse is enough. But to save yourself in an existential sewage, you must learn how to love. Nobody taught Artur how to do that.
After the premiere of All That I Love Mateusz Kościukiewicz was compared to such film stars of the recent cinema as Leonardo di Caprio or Robert Pattison ('I hate it. I have my own name, I am original, not a copy' - he defends himself in an interview), while in his role in Mother Theresa of Cats the actor was viewed as James Dean or the young Zbigniew Cybulski. The next film with his participation Shameless by Filip Marczewski hit cinema theatres in 2011. This time the protagonist played by Kościukiewicz falls in love with his older sister.
After Shameless came Małgorzata Szumowska's In the Name Of... where the young actor plays a boy in an ambiguous relationship with a priest (played by Andrzej Chyra). In 2013 Baczyński (dir. Kordian Piwowarski) premiered as well - a fictional essay about the tragic poet, portrayed by Kościukiewicz, and the nostalgic Bilet na księżyc / Ticket to the Moon directed by Jacek Bromski. Kościukiewicz played the main part in Francesco - an Italian TV series about St. Francis, directed by Liliana Cavani, alongside Rutger Hauer. In 2015 he appeared in Filip Bajon's Damaged and Jerzy Skolimowski's 11 minutes. He also debuted as a screenwrite, co-authoring the script of Maciej Bochniak's Disco Polo.
Mateusz Kościukiewicz has already shown on the big screen that he can both play emotions and play with the viewers' emotions. On November 8, 2010 he was awarded the prestigious Zbyszek Cybulski Prize. And yet, he continues to hone his craft, opening himself to a variety of forms. Theatre director and producer Krzysztof Warlikowski invited the young actor to join the cast of his latest performance The End, which premiered on September 30, 2010.
The year 2017 was a busy time for the actor – three films starring Kościukiewicz in the leading role hit the screen. Szumowska's Mug was a challenge – the actor played a man who undergoes a face transplant after a very serious accident at work. Kościukiewicz also portrayed the football player Jan Banaś in Jan Kidawa-Błoński's sports biopic Stars. In the thriller Amok, directed by Kasia Adamik, Kościukiewicz played a writer who vents his bloody instincts through his work and starts playing mind games with the policeman looking into him (Łukasz Simlat played the officer).
Kościukiewicz also appeared in the British film The Informer – a thriller about an FBI agent who investigates a Polish gang.
Kościukiewicz and Maciej Bochniak joined forces again and co-wrote the eastern Magnezja (2020). Kościukiewicz also formed another interesting duo while working on the film – he and Dawid Ogrodnik play conjoined twins bound by the ribcage.