From 16 September 2019 to 22 October 2022 she served as the Undersecretary of the Ministry of Economy and Finance in the Conte II and Draghi governments.

Her professional experience began in 1986 as a researcher in Political Economics, specializing in Public Finance, at the University of Brescia.

Guerra participated in working groups and committees established by the Ministry of Finance from 1989 to 1999, focusing on the taxation of capital income and companies.

In 2006, she chaired the commission on the taxation of capital and various financial incomes, established by the Ministry of Economy and Finance.

On 28 November 2011 Guerra joined the Monti government as the Undersecretary of the Ministry of Labor and Social Policies.

In April 2023, she became a member of the new secretariat of the Democratic Party led by Elly Schlein, with responsibility for labor policies.