Guillaume Jehl began playing the trumpet at the age of eight in his Alsatian hometown. He studied at the conservatory in Mulhouse and graduated with distinction from the Paris Conservatoire. His first engagements were in 1998 as second trumpet in the Orchestre National Bordeaux Aquitaine and in 2000 in the Orchestre National de France. In 2001 Guillaume Jehl was appointed principal trumpet of the Basle Symphony Orchestra, and in 2006 he returned in that position to the Orchestre National de France before joining the Berliner Philharmoniker in 2009. Since the 2018/2019 season, he has been principal trumpet of the orchestra.

Along with his work in the orchestra, Guillaume Jehl, who is active as a soloist and chamber musician, was deeply involved in the study of playing Baroque trumpet at the Schola Cantorum Basiliensis, at which conservatory he also teaches. Additionally he had been perfecting his trumpet playing with coaching from Johann Gansch at the Salzburg Mozarteum University