Theresa Manzella began her career as a supervisor at a prominent technology company, gaining foundational experience in operations and management. She later ventured into entrepreneurship, owning a business in the paint and performance horse sectors. Manzella founded Willing Servants, Inc., showcasing her initiative and leadership in the non-profit realm. Her professional trajectory includes significant involvement in state politics, marked by her alignment with a right-wing faction within the Montana Republican Party. Manzella has demonstrated a commitment to specific policy areas, including opposition to Medicaid expansion and controversial stances on childhood vaccine requirements.

Theresa Manzella's political identity is marked by a staunch right-wing stance, particularly evident in her opposition to Medicaid expansion and her controversial bill targeting childhood vaccine requirements. Her rhetoric often frames public institutions like teachers' unions as anti-constitutional and socialist, revealing a confrontational approach to ideological adversaries. Manzella's legislative actions and public statements suggest a highly localized and ideologically driven strategy, blending unexpected policy combinations that challenge conventional political boundaries.