Aresimowicz served in the United States Army Reserve as a combat medic, and was honorably discharged after over a decade of service.

In addition to his part-time job at the Connecticut General Assembly, Aresimowicz is employed by AFSCME Council 4a, which represents state and municipal workers, where he serves as the education coordinator, teaching classes on organizing and bargaining.

[2][3] Upon his accession to House Speaker, the Republican State Central Committee argued that Aresimowicz had an untenable conflict in his ability to properly lead the House of Representatives and confront the insurmountable and rising costs of employee labor agreements, pension contributions and health care costs, because of his close connections to Connecticut's public sector union.

“I believe that UConn has the checks and balances in place to ensure that no one is taking advantage of this situation.”[7] The State Ethics Board called this loophole amendment “An affront to all Connecticut citizens.

"[8] In January 2021, following his retirement from the Connecticut General Assembly, Aresimowicz took a job working for Gaffney, Bennett and Associates.