[citation needed] Veltroni, a professional journalist, was editor-in-chief of L'Unità, the newspaper of the Democratic Party of the Left (PDS) from 1992 to 1996.

[8] By 2007, Veltroni was widely considered one of the most popular centre-left politicians in Italy, and often singled out for the leadership of the Democratic Party (PD), despite his statements that he would not accept such position after his tenure as mayor would end.

Furthermore, the strongest of his possible contenders, Pier Luigi Bersani, which polls showed as having a 50% support in regions of Central and Northern Italy,[9] withdrew to avoid a "confusing candidacy".

At this occasion, he introduced the four key issues his programme would address: environment, generational pact, education, and public security.

[11] Veltroni was elected as the first leader of the newly founded PD on 14 October 2007, winning an open primary with around 2.6 million votes, or 75.8%.

[17] On 17 February 2009, following clashes within the party and only a day after a heavy defeat of the PD in the 2009 Sardinian regional election,[18] Veltroni announced his immediate resignation from his leadership post.

[1] The Constituent Assembly of the party subsequently convened on 21 February 2009 and elected Veltroni's former deputy Dario Franceschini as the new secretary.

In 2006, he received the title of Cavaliere di Gran Croce (Knight of the Grand Cross) from the then-Italian president Carlo Azeglio Ciampi.