Cucinelli grew up in a rural agricultural community outside of Perugia. His childhood home had no electricity or running water. Cucinelli dropped out of engineering school at age 24, choosing instead to read philosophical texts on his own. Cucinelli's first product was cashmere sweaters in bright colors. In 1977 he started making dyed cashmere in a small workshop. He founded Brunello Cucinelli SpA in 1978 with the Italian lira equivalent of about $550; after the initial public offering of Brunello Cucinelli SpA his personal net worth exceeded $1 billion.

Cucinelli is married to his hometown sweetheart Federica, and the couple have two daughters: Camilla and Carolina. Cucinelli cites the Meditations by Marcus Aurelius as a book that has strongly influenced him. His personal style icons are Gianni Agnelli and John F. Kennedy Jr. On the wall in his office are images of Socrates, Confucius, Constantine, Palladio, Dostoyevsky, Gandhi, Martin Luther King Jr., Kafka, John F Kennedy, and the Pope. Esquire magazine named him among the top ten best dressed men alive in 2017. Twice each year on the occasion of Florence's Pitti Uomo trade show, Cucinelli hosts a dinner at Villa Palmieri in a small Tuscan town five miles from the city.