This versatile man became one of the foremost representatives of Modernisme. Born into a cultured, well-off family, he was the son of a bookbinder and publisher in whose workshop he first came into contact with art and learned about the arts of bookmaking. He studied exact, physical and natural sciences in Barcelona and then began engineering in Madrid, but he soon gave this up to enrol in architecture and qualified in 1873.

Upon his return to Barcelona he joined the Barcelona School of Architecture, which opened in 1875, as a lecturer and taught there throughout his professional career, becoming the School's director for 20 years until 1920. During this period his students included J. Puig i Cadafalch and A. Gaudí.

As soon as he joined the School he started contributing to various publications of the time with articles setting out his ideas on architecture. However it was an article entitled "En busca de una arquitectura nacional" ("In Search of a National Architecture"), published in La Reinaxença in 1879, in which he propounded his idea of a Catalan national architecture, that made the biggest impact.

His architectural production in Barcelona began with a building for the Montaner i Simón publishing house (1881-1886; Aragó, 255; currently home to the Antoni Tàpies Foundation) and from then on he was extremely prolific. His work in Barcelona includes the restaurant for the 1888 Universal Exhibition, given the name of Castell dels Tres Dragons (Castle of the Three Dragons, Parc de la Ciutadella; now the Natural Science Museum); Palau Montaner (1891-1896;Mallorca, 278); the Hospital de la Santa Creu i Sant Pau (1902-1930; Sant Antoni Maria Claret, 167), which was continued by his son Pere Domènech i Roura (1912-1930); the alterations to Fonda Espanya (1903; Sant Pau, 9-11); the Palau de la Música Catalana (1905-1908; Palau de la Música, 4-6); Casa Lleó Morera (1905; Passeig de Gràcia, 35), and Casa Fuster (1908-1911; Passeig de Gràcia, 132). His production also extended to Reus, with such outstanding buildings as the Pere Mata Psychiatric Institute (1898-1922; Passeig Briansó, s/n) and Casa Navàs (1901-1907; Plaça del Mercadal, 5), and Canet de Mar, with Casa Roura (1889-1892; Riera de Sant Domènech, 1).

He was commissioned, especially in the latter part of his career, to restore a number of public buildings, such as the Saló de Cent in Barcelona Town Hall and La Llotja, the Barcelona School of Fine Arts.

All his works are characterised by a great blossoming of the decorative arts; the architect's desire to create an all-embracing, unitary whole in which all the crafts had their place.

As a concerned man involved in his culture he was an active participant in Catalan politics. He was a deputy in the Spanish parliament on several occasions, a leader of the Lliga Regionalista (Regionalist League) and was involved in drafting the Bases de Manresa, a proposal for an Autonomy Statute for Catalonia.

He was also a distinguished historian and heraldist, and author of several publications on Catalan history and art, mainly covering the medieval period.