[2] About 1816 Kirkup began to suffer from pulmonary weakness, and; after his father's death, visited Italy.
[2][3] Kirkup became a leader of a literary circle in Florence and took up residence at the Casa Carovana, a palazzo near the Ponte Vecchio.
Walter Savage Landor, Robert and Elizabeth Browning, Giovanni Aubrey Bezzi, Edward John Trelawny, Joseph Severn were his friends.
[2] On Italian unification, Kirkup was created cavaliere of the Order of Saints Maurice and Lazarus; he subsequently affected the title "barone".
He drew many portraits of his friends, including Trelawny and the journalist John Scott, and in 1844 made a self-portrait.
[2] In 1840 Kirkup, Bezzi, and the American Henry Wilde, had permission to search for the portrait of Dante, painted according to tradition by Giotto, in the chapel of the Palazzo del Podestà in Florence.