Born in 1977 in Geneva, Guillaume Lagger received in 1989 a small diatonic harmonica as a Christmas gift from his oncle Jacky Lagger, a singer and multi-instrumentalist  from the Wallis Kanton.


Drawn by the blues Guillaume learns to blow this instrument almost totally by himself and soon accompanies his brother Greg who got a guitar somewhat earlier. After a while the group Reggal is born with Christian Fürst on bass guitar. The group plays folk blues songs composed by Greg who sings in English. Between 1994 and 2000 they perfom at bars and small scenes and record two albums “The Reggal Harmonica” in 1995 and “Trio” in 1999.

Next to Reggal, up until today, Guillaume plays occasionally with Jacky Lagger on albums and on stage. Like e.g. at the Paléo Festival de Nyon with the show “Les Terrestres Extras”.

Still exploring his instrument Guillaume also continues to play together with a variety of musicians and in 1997 he meets a group that will gradually become more important to him: “L’Ironie du Son”.

Also during that time he discovers a new passion: percussion. Some time after acquiring his first set of congas he meets L’Ironie du Son backstage at L’Undertown in Geneva.
That is the start of a long collaboration in several stages and line ups. Little by little Guillaume takes his harmonica out of its pocket till he finally plays it exclusively for the 2003 album “Nuage Fou”. L’Ironie du Son is still his “main” group where he has developed a style of his own after four albums and more than one hundred concerts.

Guillaume Lagger has been extending his musical activities during the same time to collaborations with the Senegalese singer Kara from 1999 to 2002, Imago, Jewish music with jazz influences from 2004 - 2005, with singer Mr. Peach from 2006 - 2007 and Vagalatschk, exploring Balkan and klezmer sounds from 2006 - 2008.

Since the beginning of 2006 he accompanies the Pierre Lautomne, a singer from Geneva. During 2006 the first solo album of Jonas, the rapper of L’Ironie du Son sees its release and a group containing eight Swiss and African musicians is formed around him for a tour. Guillaume is one of them, mostely on percussion and sometimes on harmonica.

At the end of 2007 Guillaume joins the group André Bachleda & The Technicolor Orchestra and since the summer of 2008 he plays with Canadian bluesman Marc-André Léger who has settled in Geneva recently.

2009 has another musical adventure starting for Guillaume as he teams up with Raaga Trio for the recording of their first album.