Visintini joined the Italian Naval Academy in Livorno in 1933, and received his appointment as Ensign in 1937. Initially assigned on surface ships, he participated in missions during the Spanish Civil War; he then served on the submarines Narvalo and then on Atropo. While on the latter, in April 1939, he participated in the operations for the Italian invasion of Albania. On 10 June 1940, when Italy entered World War II, Visintini was serving on the submarineTorelli, and participated in its first mission in the Atlantic Ocean. On his return, he asked to be assigned to the Tenth MAS Flotilla in La Spezia, where he became assault craft operator. In 1941 he was promoted to Lieutenant and was given command of the "Ursa Major squadron", deployed against the British naval base at Gibraltar. In the night between 25 and 26 May 1941, Visintini led a first attack on Gibraltar with three SLC manned torpedoes released from the submarine Scirè ; the raiders managed to enter the harbor, but the operation failed due to a combination of mechanical breakdowns suffered by the SLCs and sudden illnesses that seized two of the operators. Visintini and his companions had to swim to the shore, then they returned to Italy with the help of agents from the Italian Navyintelligence service. In the night between 19 and 20 September 1941, Visintini led another attack against Gibraltar, again with the use of three SLC released by the Scirè. This time, the operation resulted in a success: Visintini and his partner Giovanni Magro mined and damaged the naval tanker RFA Denbydale, which remained afloat but was considered a constructive total loss because of the severity of the damage, while the other two SLCs sank the tanker Fiona Shell and severely damaged the armed merchant Durham. The operators then destroyed the SLCs and swam to the coast, where they were again assisted by Italian agents who helped them to return to Italy. In the summer of 1942, when it was decided to stop using submarines for the approach of SLCs to the port of Gibraltar, instead resorting to turn the steamer Olterra, interned in Algeciras, into a secret floating base for SLCs, Visintini was tasked with directing the transformation, as well as being given command of the SLC group that would operate from the ship. At 23:15 on 7 December 1942, Visintini left Olterra for operation "B.G.5", and steered his manned torpedo towards the port of Gibraltar, with the aim of mining the battleship HMS Nelson. He and his partner, Leading Seaman Giovanni Magro, managed to overcome the external obstructions and to enter the harbor, but were both killed by the depth charges thrown by British surveillance to ward off Italian raiders. Visintini and Magro were both awarded a posthumous Gold Medal of Military Valor. Their bodies were recovered by the British and buried with full military honours. The Marina Militare named a De Cristofaro-class corvette, F 546, after him.
