He studied under Jean-François Portaels from 1859 at the Académie Royale des Beaux-Arts in Brussels,[2] and in 1869 won the Prix de Rome.
[3] In 1868, he was one of the founding members of the Société Libre des Beaux-Arts in Brussels.
Agneessens later built up quite a career in Saint-Petersburg, but returned to Brussels in the 1880s.
In the latter part of his life he suffered from a mental disorder.
[3] His works include Standing Male Nude (1870), Ladies by a Piano, and Bloemenstilleven.