Through his father's collaborations under the court architect Bernardo Buontalenti, Giulio Parigi was trained in the practice of architecture. Following Buontalenti's death (1608) he designed and oversaw the creation of the elaborate ephemeral decorations for court festivities, in which he was an influence on Inigo Jones, who was providing similar services in the same years for the court of James I of England. Giulio worked on the Boboli Gardens, constructing the Grotto of Vulcan (Grotticina di Vulcano, 1617) and laying out the second axis of the Boboli Gardens, at right angles to the first, with the bosquets on either side.
Giulio rebuilt the Villa di Poggio Imperiale (1620-1622), and constructed the Ospedale dei Medicanti (1621), the church of San Felice in Piazza (1634-1635) and worked on projects for the Palazzo della Crocetta for Maria Maddalena de' Medici. His is also the grand stairs of Palazzo Gianni-Lucchesini-Vegni (1624).
Giulio's son, Alfonso's grandson, Alfonso Parigi the Younger was also an architect and engraver.