Kolar also serves as a lieutenant commander in the United States Navy Reserve.

[2][3] In 2018, Kolar was selected as a United States magistrate judge for the Northern District of Indiana in the Hammond division.

[6] On July 27, 2023, President Joe Biden nominated Kolar to serve as a United States circuit judge of the United States Court of Appeals for the Seventh Circuit.

[7] President Biden nominated Kolar to the seat vacated by Judge Michael Stephen Kanne, who died on June 16, 2022.

[10] During his confirmation hearing, he was questioned by Senator Marsha Blackburn over a case that he presided in 2019.