Born in Richmond, Surrey in 1745, Richard Fitzwilliam, the 7th Viscount Fitzwilliam of Merrion, was a patron and musical antiquarian. He was educated at Trinity College, Cambridge and was an accomplished draughtsman and harpsichordist. Following graduation, Fitzwilliam spent time in Paris, Spain, the Netherlands and Italy. It was during his travels that he built up his impressive collection of important illuminated manuscripts, paintings, prints and drawings. His passion for music lead him to serve as director of the Concerts of Ancient Music in London, and he was also one of the instigators if the Handel Commemoration of 1784. In 1789 he was made a fellow of the Royal Society.

By this time, Fitzwilliam had succeeded his father, also Richard, in his Irish titles and estates. Viscount Fitzwilliam, of Merrion in County Dublin, was a title in the Peerage of Ireland. It was created in 1629 for Thomas Fitzwilliam. The family seat was Mount Merrion House in South County Dublin.

During his time as Viscount, Fitzwilliam commissioned the development of part of South Dublin. His developments included an Act to enclose Merrion Square in 1791, the design of Fitzwilliam Square in 1789 and an Act to enclose it in 1813. He also commissioned a new church for Booterstown in 1812, called the Church of the Assumption.

Fitzwilliam never married, although he had three children with the French ballet dancer Anne Bernard (Mademoiselle Zacharie), and so upon his death in 1816 his titles passed to his younger brothers. However, the title 'Fitzwilliam of Merrion' became extinct in 1833. His Estate passed to his cousin the 11th Earl of Pembroke and from then on was known as the Pembroke Estate.

The 7th Viscount Fitzwilliam is perhaps best remembered for his bequest of his extensive library and rich and valuable art collection to the University of Cambridge, together with enough funds to house them. As result, the Fitzwilliam Museum at Cambridge was formed.