As chief founder of the well-known Roman Academy of the Arcadians, he had a considerable share in the reform of Italian poetry, which at that time was dominated by the baroque extravagance of the poets Giambattista Marino and Claudio Achillini and their school.

Guidi, Giovanni Mario Crescimbeni, and the critic and jurisconsult Gravina attempted to foster a straightforward use of language.

[1] While his early verse shows the influence of Marino, he later cultivated the Pindaric manner of Chiabrera, producing canzoni of free stanzaic form.

[1] Guidi's poetical version of the six homilies of Pope Clement XI, was severely criticized by the satirist Settano.

[1] Guidi was honoured with the special protection of Ranuccio II, duke of Parma, and of Queen Christina of Sweden.