Jean Lesieur graduated from the Journalism School of Columbia University (1974) and started his career in Canada as a reporter for the French Canadian weekly La Liberté (Winnipeg, Manitoba).
In 1976, he started working in France as a reporter for the Sports Daily LEquipe.
One year later he joined the weekly news magazine Le Point as an international correspondent and soon became Associate Editor.
He moved to LExpress in 1989 as a senior reporter and was appointed Managing Editor of the magazine in 1994. In 1995, he was named Executive Editor of the French magazine, GALA.
From 1999 to 2004, he headed the largest-selling TV magazine in France, Télé 7 jours and then joined the Executive board of HACHETTE-FILIPACCHI Magazine Group as Editorial Advisor in New York and Paris.
Jean Lesieur had joined FRANCE 24 in 2006 to take part in the launch of the channel as Executive Producer in charge of magazines and talk shows. In 2009, he had left FRANCE 24 to pursue other interests in the United States.
Jean Lesieur is also the author of an investigative novel published in 2008 Laffaire Carolyn Black (JC Lattès).