In 1878, with his architect's diploma, Gaudí received his first official commission from Barcelona Council, to design street lamps part of the urban equipment of the city. At the same time Eusebi Güell's father in law, Antonio López, Marquès de Comillas, commissioned him with the project for the furnishings for the family chapel and vault, near the Palau de Sobrellano, in Comillas (Cantabria).

He had more work as an architect after 1883, the time when he was working as a draughtsman and associate of the architect Joan Martorell. That was when he was commissioned with the construction of Casa Vicens, Villa El Capricho in Comillas, and the continuation of the work on Expiatory Church of La Sagrada Família was entrusted to him. Shortly afterwards he received the first major commission from Eusebi Güell, his future patron and main customer, which gave him the building of the pavilions at the Güell Estate, followed by Palau Güell, in Carrer Nou de la Rambla.

In 1887 he began to plan the Episcopal Palace in Astorga and the following year the works on the Teresian School in Barcelona. He then built the Casa de los Botines in León and in 1892 worked on a religious building for the Franciscan friars in Tangier, the Catholic Missions of Africa, which he never completed.