This study draws on the unpublished correspondence between Michelangelo Buonarroti the Younger, a Florentine poet and grandnephew of the artist, and the Barberini family, in an attempt to examine the wider concepts of cultural clientelism and brokerage networks in the early modern process of cultural dissemination (in the areas of literature, music, theater, painting, architecture, and science) in Florence and Rome. Reconsidering the definition and role of a Seicento cultural broker added to the traditional model of patron and client, it analyzes Michelangelo the Younger’s activity as broker, patron-broker, and broker-client in connection with such significant figures as Maffeo Barberini (the future Urban VIII), Galileo, and the painter Lodovico Cigoli, exploring the ways in which these roles supported his personal commitment to promote his family’s social status and revealing the fluidity of roles in the patronage system. By obtaining Barberini patronage for his theatrical works and public recognition of the mythology of his illustrious forebear, Buonarroti’s cultural brokerage supported these dynastic ambitions. Spanning nearly half a century, this archival documentation casts new light on a little-known, but significant, area of Italian social relations and suggests directions for further research on other Seicento cultural brokers and new definitions for a broader concept of cultural brokerage in early modern Italy.