Gustave’s father, born Le Sénéchal, added Kerdréoret to his name between 1839 and 1840, and became owner of the castle of Kerroux Languidic. Le Sénéchal de Kerdréoret was a student in Paris and attended classes from Jules Achille Noël (1815-1881) from 1847 before joining the navy. He made many sketches and notes during his travels throughout his career, which he transposed into carefully constructed paintings.

Gustave Le Senechal de Kerdreoret first exhibited at the Paris Salon in 1869 and received several medals; these included an honourable medal in 1881, a third class medal in 1883 and a second class medal in 1888.

He wanted to perfect his technique and took lessons from Pierre Auguste Cot (1837-1883) in 1871 and befriended Antoine Vollon (1833-1900) in the 1880s who also gave him tips and advice.

In 1890 Gustave Le Sénéchal de Kerdréoret became the Official Painter of the French Navy, a title awarded by the Minister of Defence to artists who have devoted their talent to represent the sea.