Grignani studied architecture but became more interested in graphic design. He devoted himself to experiments in optical and visual design, painting and photographs. The Milan printers Alfieri & Lacroix allowed him a free hand with his typographic experiments. In later years he devised outstanding and novel photo compositions, based on optical systems he invented. He influenced many of his contemporaries. He worked as art director for Bellezza d’Italia, the house organ of Dompé pharmaceuticals, and Publicità in Italia. He was also an exhibition designer. He had more than forty-nine solo exhibitions from 1958 in Italy, the UK, Switzerland, Germany, the US and Venezuela. He was the winner of the Palma d’Oro della Publicità (1959) and the gold medal at the Milan Triennale. Grignani also won an award at the Warsaw Poster Biennale (1966) and the Venice Biennale (1972). Many museums in Italy, as well as Hamburg and Caracas, have acquired his work.