Capelo first exhibited in 1996 and since then she has exhibited at numerous group and solo exhibitions. Although her paintings give the impression that they could be anywhere, her landscapes are always based on actual places. Her favourite locations for inspiration are the Baixo Alentejo Province of Portugal, the Piedmont region of Italy, and Extremadura in Spain.[4][5]
In 2013 she received a grant from the Calouste Gulbenkian Foundation to carry out a project called Da Sombra dos Montes (From the shadow of the mountains), as part of the foundation's "Support for Visual Arts – Artistic Research Projects" Programme. At the end of 2021 the foundation's Modern Art Centre (CAM) purchased two of her paintings for its collection. In 2021 she was exhibited as part of the Calouste Gulbenkian Museum's exhibition entitled All I want: Portuguese Women Artists from 1900 to 2020.[5][6]
In 2022 Capelo was the winner of the Fundação Luso-Americana - Para o Desenvolvimento (Luso-American Development Foundation– FLAD) Drawing Prize, winning €20,000. All three of the judges selected her as the winner, observing that "Maria Capelo's work reveals a curious sense of adventure, producing images that are only apparently simple, from which she is able to recreate the landscape tradition in an innovative and surprising way".[1]