This was a problem faced by even the best-known artists of the day, such as Almada Negreiros and Mily Possoz, who had to resort to more commercial activities, such as doing book illustrations.

He employed a bold style, often using strong shades of green, browns and grey, in producing mainly urban landscapes, as well as abstract still-life work.

[1] Hogan was also an important printmaker, especially using woodcuts, and giving along with other contemporary artists an impulse to the growth and teaching of this art form, almost forgotten in his time in Portugal.

He is represented in the collections of the National Museum of Contemporary Art of the Gulbenkian Foundation, the Casa Muséu Anastácio Gonçalves, the former studio of the painter José Malhoa, and the Museu Nacional de Arte Contemporânea - Museu do Chiado, all in Lisbon and in the National Museum Soares dos Reis in Porto, as well as in several private collections.

Outside Portugal, his paintings are in the Hudson River Museum in New York City and the Museo Nacional Centro de Arte Reina Sofía in Madrid.