Treccani was born in Milan on 26 August 1920, son of Senator Giovanni Treccani of Alfieri, founder of the Treccani Institute, he began at a very early age to be part of the groups of avant-garde art and anti-fascist.
Founder and director, at 18, of the magazine "Corrente", suppressed in June 1940 at the outbreak of the war, he exhibited his first works at the Bottega di Corrente with his friends Birolli, Guttuso, Migneco, Sassu and, later, with Cassinari and Morlotti at the Galleria della Spiga e Corrente. The first personal exhibition, held at the Galleria Il Milione in Milan, dates back to 1949. After the Resistance, which he actively participated in, he was the animator of the group "Painting" and editor of the magazines "il 45" and "Realismo", directed by Raffaele De Grada. In the '50s, in addition to exhibiting several times at the Venice Biennale, he participated in the exhibition of realists at the Leicester Gallery in London and exhibited in New York with a solo show at the Heller Gallery. In this period the themes of his painting are characterized by the encounter with the Calabrian rural reality, known directly in the long stays in Melissa, started at the time of the first occupations of the lands in the South, and the industrial urban landscape of Milan and Paris, places on which he will return several times over the years.
In 1963 one of his works was exhibited at the exhibition Contemporary Italian Paintings, set up in some Australian cities.
From the 60’ onwards the flourishing of the works and the multiplication of initiatives bear witness to the uninterrupted, human and artistic commitment of Treccani, characterized by an untiring action to spread the culture and the artistic debate, from a concrete adherence to the situations of life and a profound love for men and things. Among the works of this period are the five large canvases inspired by "La luna ei falò" by Pavese (1962-63), the cycle of works "Da Melissa a Valenza" (1964-65), the series of watercolors dedicated on a trip to Cuba in 1965, the great painting Popolo di volti (1969-75), which began on the day of the funeral of the victims of the Piazza Fontana massacre; later, in 1976, the great exhibitions of Volgograd, Moscow and St. Petersburg. Since then, Treccani has developed in many forms the different seasons of his artistic research, continuing to operate and exhibit in small and large centers, in Italy and abroad, and alternating this "itinerant" activity with habitual creative stays in Macugnaga and Forte dei Marmi, countries to which the artist has been strongly linked in life and painting. In 1978 he founded the Corrente Foundation, center of cultural initiatives, exhibitions, debates in the various fields of culture and art, as well as a center for collecting and studying documents relating to the period between the birth of the movement and the years of Realismo.È in 1982 his monographic presence at the group Maestri e Giovani at the center of Art Culture and Costume in Milan, with Mauro Reggiani, Ottone Rosai, Galliano Mazzon, among others, and the young Nino Bonacina and Lino Riccardi. In 1989 the City of Milan dedicated a wide anthological exhibition to the artist at Palazzo Reale, while another important retrospective of his works was hosted at the Bandera Foundation in Busto Arsizio in 2003. In 2004 the cycle of large windows "Energy , lights and colors "exhibited in Lugano, Riga, Budapest and Prague, while in 2006 the Municipality of Forte dei Marmi set up the exhibition" Mutations of Realism - Unpublished Works 2003-06 "at Fortino, the result of a renewed research of shapes that has its center in color. In 2008, again at Palazzo Reale, Treccani took part in the exhibition "Corrente, le parole della vita." Works 1930-1945 "with a room dedicated to his paintings of the period. A major anthological exhibition, curated by Giorgio Seveso, has inaugurated the renovated rooms of Palazzo Barberino in Montichiari (BS), the birthplace of the artist's father, Senator Giovanni Treccani degli Alfieri. Among the most recent exhibitions we mention the exhibition "Words and painting: Ernesto Treccani meets poetry, the epic and the novel" at the Pinacoteca Civica of Savona from December 2011 to March 2012, always curated by Giorgio Seveso. He died in Milan on 27 November 2009.