[4] Izambard is an active member of the French organization AMTM (Assistance Médicale Toit du Monde) and global ambassador for the Sanfilippo Children's Foundation.

He grew up in a poor single-parent household and lived with his mother in a room little bigger than 100sqft on the top floor of a block of apartments in Paris with her great-grandmother.

[8] Izambard started his career as a pop musician in France, releasing a solo album called Libre[3] and his song "Si Tu Savais" was ranked first in French Hit Charts.

[10] Izambard performed in February 2002 in Richard Cocciante's musical Le Petit Prince, where he played the role of the Business Man.

While recording his second solo album after collaborating on Le Petit Prince, Izambard attended an audition for the musical The Sun King.

While waiting, he met Geraldine Larrosa, (Innocence) and her then-partner Carlos Marín, who spoke to him after hearing Izambard sing in online videos.

Izambard said to himself "Je ne regrette rien (I have nothing to lose)",[11] accepted and devoted himself in the global musical quartet Il Divo in December 2003, along with Urs Bühler (Switzerland), David Miller (US) and Carlos Marín (Spain).

On 12 December 2008, Il Divo performed their new song at the Swedish Idol 2008 finale in the Globen Arena in Stockholm, Sweden.

[14] The Paraguay show was Il Divo's biggest capacity performance to date and took place on 20 December 2011, at the Defensores del Chaco Stadium in Asuncion, for 33,900 people.

[18] On 19 July 2014, Il Divo performed before a capacity crowd at Edinburgh Castle esplanade where a pop festival took place ahead of the 2014 Commonwealth Games.

[19] On 23 March 2015, it was announced that Il Divo was the winner of the 2015 Silver Clef Award, giving them the coveted Classic PPL.

Izambard is an active member of two charities: the French organization AMTM (Assistance Médicale Toit du Monde)[39] which helps poor children in Nepal and India, where during one of his campaigns to raise funds in September 2008, Seb raffled off several of his Armani suits, and the Australian Sanfilippo Children's Foundation organization, of which he is global ambassador.

[41] A few months before the wedding, on 20 March 2008, Sebastien and Renée became parents of twins, Rose and Luca,[42] who were born in Port-Royal near Paris.