Career
He served as mayor from 1994 to 2001 and from 2005 to 2009. Gladu started his career as a firefighter for Ville Jacques-Cartier in the 1960s. He first served as a city councillor in 1982, and during the 1980s was the president of the Société de transport de la Rive-Sud de Montréal (now the Réseau de transport de Longueuil).
Gladu served as the mayor of Longueuil from 1994 to 2001.
The pre-2001 city of Longueuil merged with the surrounding municipalities of Boucherville, Brossard, Greenfield Park, Le Moyne College, Saint-Bruno-de-Montarville, Saint-Hubert and Saint-Lambert on January 1, 2002. Jacques Olivier was elected mayor of the merged municipality.
In 2005, Boucherville, Brossard, Saint-Bruno-de-Montarville and Saint-Lambert voted to demerge from Longueuil. The demerger took effect on January 1, 2006.
On April 19, 2009, Claude Gladu announced that he would not seek re-election as mayor of Longueuil.
He and his party instead threw their support behind former Longueuil City Council member Jacques Goyette. Goyette lost the election to Caroline Street-Hilaire.