He was a member of Jean Drapeau's Civic Party. He was elected to Montreal's City Council in 1978 in Saint-Jacques, a district with a significant amount of gay residents. He was re-elected in 1982, but was defeated by RCM candidate Raymond Blain in 1986. In November 1992 though, he won a by-election in the same district.
When the Civic Party ceased to exist and merged with Jérôme Choquette's Parti des Montréalais (Montrealers’ Party), Forcillo decided to support Pierre Bourque and join Vision Montreal. He was re-elected in 1994 and became Deputy Chairman of Montreal Executive Committee.
In 1998 he first announced that he would support Jacques Duchesneau for Mayor, but eventually changed his mind. He ended up being re-elected as a candidate for Jean Doré's Équipe Montréal (Team Montreal).
In 2000 Forcillo sat again as an Independent and joined Gérald Tremblay's Montreal Island Citizens Union (French: Union des citoyens et des citoyennes de l’Île de Montréal or UCIM; the party is now known as Union Montréal).
He has been a Member of Montreal's Executive Committee since then.
On June 25, 2008, Tremblay named Forcillo as the Executive Member responsible for the city's finances following a re-organization that was made necessary following the resignation of the president of the Executive Council, Frank Zampino. 
He ran again in the 2009 Montreal municipal election for Union Montréal in the adjacent district of Peter-McGill.
Raymond Blain (RCM)
|City Councillor, District of Saint-Jacques
Robert Laramée (Vision Montreal)
|City Councillor, District of Sainte-Marie—Saint-Jacques