In this capacity, he acts as spokesperson for environmentalist and pacifist demands, for the defense of the city's historic villas and against the construction of the new San Nicola stadium.

[1] In 1986 in Finale Ligure he signed the founding act of the Federation of Green Lists and the following year he was involved in the victorious referendum campaign on nuclear power.

After failing re-election in the 1994 elections, Leccese manages to be elected at the Chamber of Deputies in the 1996 elections; he is appointed vice-president of the Foreign and Community Affairs commission, dealing with foreign policy, protection of human rights and democratic guarantees, and carrying out some missions as an "international observer" in conflict zones in Bosnia, Albania, Serbia, Turkey and Iraq.

[2][3] After the 2001 elections, disappointed by the electoral defeat in his constituency and in contrast with the new leadership of Alfonso Pecoraro Scanio in the Greens, he distanced himself from politics.

From 2007 to 2009 and from 2014 to 2023, Leccese has been the chief of staff of Mayors of Bari Michele Emiliano and Antonio Decaro.