Atinolfo was staying in Florence when he was appointed bishop by the Emperor Conrad II in February or March 1038.
His predecessor, also an imperial appointee, was Iacopo il Bavaro, was a reformer who restored the diocesan patrimony.
Nonetheless, Atinolfo signed the canons with Gerard, Bishop of Florence, of a Roman synod convened under Pope Leo IX, a reformer, in May 1050.
On 15 July 1050, while the pope was passing through Florence, the monks of San Bartolomeo met him and implored him to confirm the donation that Iacopo had made to them.
Atinolof was last recorded in July 1057 at a synod of Tuscan bishops in Arezzo under Pope Victor II.