Pellegrini was born on October 6, 1977 in Banská Bystrica. He is a graduate from the Matej Bel University in Banská Bystrica and the Košice University of Technology, both in finance, banking, and investment.
From 2006 he served as Smer MP until 2012, when he was selected to become the Finance Ministry’s state secretary. Following that, he has changed jobs several times: in July 2014 he replaced Dušan Čaplovič as education minister, and after a brief stop there he moved to parliamentary speaker at the end of the same year.
Pellegrini, a politician with Italian roots, is an economist with a background in finance and banking. Between 2002 and 2006 he was deputy assistant for Ľubomír Vážny and in 2006 Smer elected him to parliament. Since 2012, he served as state secretary of the Finance Ministry. In 2014 he advanced to the post of deputy chairman in the party.