On his advice, Guillou moved to Paris in 1862, where he attended the Académie Suisse for a short time, then found a position in the workshop of Alexandre Cabanel.
[2] After his marriage to the daughter of the engraver Joseph Gabriel Tourny (1817–1880), he maintained a home in Montparnasse, but spent as much time as possible in his hometown.
Following his father's death in 1887, he built a home and workshop there, became involved in local politics and joined the board of the Musée des beaux-arts de Quimper.
[1] Over the years, the Colony attracted many artists who were either interested in maritime subjects or wanted to achieve a sort of primitivism; represented for them by the traditions of the Breton people, which had survived mostly intact from an earlier period.
Among the better-known artists who spent time there were Peder Severin Krøyer, Charles Cottet, Jules Bastien-Lepage, Pascal Dagnan-Bouveret, Amélie Lundahl, Cecilia Beaux and T. Alexander Harrison.