Born in Klaipėda, Mikalauskas started his career with his hometown team Neptūnas and the Vladas Knašius Basketball School.
[2] This became his breakout season as he averaged 18.1 points and 7.1 rebounds per game while leading Feyenoord to a fifth place.
[3] On July 7, 2021, he has signed with ZZ Leiden in the Dutch Basketball League (DBL).
[5] On July 18, 2023, he signed with Stal Ostrów Wielkopolski of the Polish Basketball League (PLK).
[6] On December 18, 2024, Mikalauskas returned to Lithuania and signed with Nevėžis Kėdainiai of the Lithuanian Basketball League (LKL).