[citation needed] Prior to her appointment as Fire Commissioner, Kavanagh spent several years with the FDNY, involved in the agency's response to major incidents including the Ebola outbreak of 2014 and the 2020 COVID-19 pandemic.

[4] Kavanagh's tenure as commissioner was met with opposition by rank-and-file members of the FDNY based on her relatively young age, lack of any experience as a first responder and allegations of her department's demoting older and more experienced fire chiefs.

Upon graduation from Whittier College in California with a BA in Political Science and International Relations, she moved to New York City and lived in all five boroughs, managing and campaign consulting for non-profits, community-based organizations and unions.

She was a Special Assistant to Mayor Bill de Blasio,[6] and during the 2012 United States presidential election, she served as Deputy Director in Pennsylvania on Barack Obama's reelection campaign.

[citation needed] Commissioner Kavanagh was heckled at the NYC's 2024 St. Patrick’s Day Parade after her department vowed to go after Trump-supporting FDNY members who booed New York Attorney General Letitia James at a promotion ceremony.