Born in Scotland of Italian parents, Guidi was a self-taught musician. He began his musical career in Italy where he went on to play with many leading jazz musicians and performed in major Jazz Festivals including Umbria Jazz Festival, the Aosta Jazz Festival, the Jazz Festival of Pescara and the Padova Porsche Jazz Festival.
After moving to the Netherlands, he performed in many national jazz festivals including several appearances at the North Sea Jazz Festival with both his quartet and big bands. He was the head of the jazz department of the Amsterdam Muziekschool where he led several ensemble and big band workshops for students of all ages, beginning with students as young as nine years of age. These bands included the Jazz Kidz, Jazz Juniors, Jazz Generation, Jazz Focus Big Band, and Jazz Mania Big Band. He was also co-founder of the Junior Jazz College, a collaboration between the Muziekschool Amsterdam and the Amsterdam Jazz Conservatory. Since the Jazz Department began, in 1988, his bands have won a total of 87 prizes in national and international competitions.
In 2008, Guidi co-founded the first edition of the Netherland National Youth Jazz Orchestra (NJJO) which has become an established bi-annual event.
In 2010, Guidi was awarded a Dutch Knighthood (Ridder in de Orde van Oranje-Nassau) for his pioneering work in jazz education in the Netherlands.