His Algerian great-grandfather, Ahmed Ould Cadi, who was an agha (chieftain), fought against the Ottoman caliphate before joining the French Army.

In 2001, Together with Bastien François, a professor of Political Science at Pantheon-Sorbonne University, Montebourg became the cofounder of the Convention pour la VI-ème République (C6R).

Montebourg, also supported reporter Denis Robert for his role in revealing the illegal system of double-accounts maintained by Clearstream, a clearing-house based in Luxembourg, involving high-ranking politicians.

[9] Montebourg was appointed as spokesman for Ségolène Royal's presidential campaign following his endorsement of her candidacy during the Socialist Party primary election in November 2006.

"[10] He was referring to the contradictory statements on tax policy made by Royal's partner, François Hollande, who was at the time serving as First Secretary of the Socialist Party.

In 2011, when Dominique Strauss-Kahn was released from prison and flown back to France, Montebourg urged him to apologise for embarrassing the Socialist Party.

[17] On 11 February 2014, Montebourg was among the guests invited to the state dinner hosted by U.S. President Barack Obama in honor of Hollande at the White House.

[18] On 28 May 2014, Montebourg said that if the United Kingdom "were to vote to leave the EU, France will roll out the red carpet to British investors who will flee their country.

[22] On 26 March, the French-based consulting and business analyst company, Talan, announced that Montebourg had been given a place on its strategic policy committee.

[28] Montebourg lived from 2010 to 2012 with journalist Audrey Pulvar and from 2014 until 2017 with fellow minister Aurélie Filippetti, with whom he has a daughter, Jeanne, born in September 2015.

[29] In February 2015, Montebourg was called a hero for saving several fellow diners in the New York City brasserie Balthazar from serious injury by single-handedly holding up a large mirror which had fallen from the restaurant's ceiling.