Paolo Nespoli was born in Milan in 1957. He joined the Italian Army in 1977, where he became a non-commissioned officer and parachuting drill instructor in the Military Parachuting School in Pisa. In 1980 Paolo was transferred to the 9th Assault Battalion and obtained his airborne commando brevet. From 1982 to 1984 he was stationed in Beirut, Lebanon, as part of the Italian contingent of the Multinational Peace Force. In 1985 he then resumed his University studies and left the army.

In 1988, in New York, Paolo graduated with a Bachelor of Science degree in Aerospace Engineering and a Master of Science in Aeronautics and Astronautics from the Polytechnic University of New York. He then returned to Italy and worked as a Planning Engineer in Florence, where he carried out mechanical analyses and provided support for qualifying the flying units of the Electron Gun Assembly of the Italian Space Agency. In 1990 Florence University awarded him a degree in Mechanical Engineering.

In 1991 Paolo entered the ESA astronauts corp, stationed in Cologne, Germany. There he worked as an astronaut training engineer, contributing to training the European astronauts. He was also entrusted with the design and maintenance of astronaut training material. In addition to that, he was in charge of the Astronaut Training Database, a software used to prepare astronauts and manage astronaut training. Paolo was then quickly assigned to the ESA's EuroMir project and to NASA's Johnson Space Centre. He was later appointed astronaut for the Italian Space Agency and chosen to become part of the European Astronaut Corps of the ESA.

In 1998 Paolo was transferred to NASA’s Johnson Space Centre and was assigned to the XVII class of NASA astronauts. In June 2006 he was officially assigned to the crew of the Shuttle’s mission STS-120. In 2008 he was assigned to Expedition 26/27, a long-term mission on the International Space Station which ended on May 2011. Four years later, on June 26, 2015 Paolo was assigned to the crew of Expedition 52/53. On 28 July 2017 he returned to space for the third time leaving Bajkonur at 17.41 (Italian time) aboard the Sojuz MS-05 in the direction of the International Space Station. At 23.54 (Italian time) the Sojuz capsule docked and finally at 1.57 (Italian time) Paolo entered the station. On 14 December 2017 at 09.27 a.m. (Italian time) after 139 days on the ISS he landed on board the Sojuz MS-05 in the steppe of Kazakhstan, the closest city to the landing site being Dzhezkazgan. In his three missions of 2007, 2010-2011 and 2017, Paolo spent a total of 313 days, 2 hours and 36 minutes in space.