Gianluca Vialli, the first Italian to take charge of Watford, won 59 caps for his country and many of the greatest prizes in the sport before strolling straight into top-level management. Gianfranco Zola's broad grin and bewitching feet made him one of the most popular of all Premier League players and led to several high-profile coaching positions. And now there is Beppe Sannino, who might not be the first smartly dressed, shaven-headed Italian to patrol the touchline at Vicarage Road but has little in common with either of his predecessors but a mother tongue and an underemployed barber.

Vialli was one of five children born to a multimillionaire industrialist from the rich north of the country; Sannino was one of five children born to a painter and decorator from the deprived south. Vialli was raised in a 60-room mansion; Sannino slept on the kitchen floor. By the time Vialli stopped playing he was manager of Chelsea; when Sannino stopped playing he got a job as a hospital janitor. If they both reached the same destination, they trod very different paths.

"I was born in Naples, but when I was 12 my father moved to Turin to work in the Fiat factory," says Sannino, who is preparing his side to take on the free-scoring Manchester City in the FA Cup fourth round on Saturday. "In Italy there's a big difference between life in the north and the south. In Naples we had a nice house, but there was no work. In Turin there was work, but we couldn't afford a house. Our apartment was tiny, two rooms only, on the fifth floor of a tall block, and I slept in the kitchen with my brother. My father had always dreamed of working for Fiat, but he didn't like the factory and after a year he left, and went back to decorating. There was more work for painters in Turin than in Naples. My family is a modest family, a working family. It was not an easy life, but in that period I learned everything that has brought me here."

Sannino's promise as a footballer was evident from a young age, and like Zola he was an entertainer who preferred the No10 shirt. But in 13 years as a player he never once appeared in Italy's top two divisions, passing instead between teams in Serie C1, C2 and D. He tasted greatest success as part of a celebrated attacking trio at Vogherese, and it was to Voghera that he returned when his playing career ended.

"I didn't make a lot of money from football, and I had a wife and two children so I had to work," he says. "That's what led me to the hospital. I worked for five years in a psychiatric hospital, and for five years in a civic hospital. I was always cleaning, I cleaned toilets and bedrooms and all the wards: geriatric, neonatal, intensive care. My experience over those 10 years will stay with me for ever. Because you see everything in the hospital – birth and death, pain and joy. I saw people who were fans of Vogherese, who used to come and see me play, and sometimes I saw them suffer and die. This does big things to you, inside, that don't leave you.

"Every morning I'd start work at 6am, and at one o'clock I'd finish at the hospital, get in the car, and drive 100km to Monza or wherever to coach kids. Then I'd drive 100km back, have something to eat and collapse on the sofa. My son would say: 'Mummy, why is Dad always so sleepy?' And at 5am the next morning the alarm would ring again. But I always had a dream. Not to reach Serie A, that was too much, but to become a full-time, professional football coach, to have a salary and live an honest life."

After funding his coaching for a decade by the mopping of floors and the disinfecting of toilets, Sannino realised that relatively minor ambition, but genuine success remained elusive. Then in 2007, a few weeks after his 50th birthday, he led Lecco to promotion from Italy's fourth division, now known as the Lega Pro Seconda, and the following year repeated the feat with Pergocrema. Both achievements were swiftly followed by the sack, but his next job, at Varese, changed everything. They roared to successive promotions and lost in the Serie B play-offs when on the verge of a third. It was the kind of achievement that reshapes reputations. In 2011, at the age of 54, Sannino was given his first job in Serie A, leading Siena to 14th place and the Coppa Italia semi-finals in his first season.

"I have come to understand that life gives you a road, and you must walk down it," he says. "It is already written for us. We can't all be great players, and then straight away get a coaching job. Some of us have a short journey, and some have a very long journey, and we learn different things along the way. I spent three years in Serie A, a year in B, a decade in C, a decade coaching youth teams, but you don't necessarily need all of that to get here. I am happy to have had all these experiences. This is what I have been given.

"I understand that fans and players like to see the great stars of the game, and that is why so many top players, when they stop, immediately have the opportunity to become a coach. But I have become an example in Italy of the other way, an example for all the coaches that start with nothing. If you work hard, if you do a good job, you can get there. It's very difficult, but it can happen. I hope my story can be like a bright star, that everyone who wants to be a coach in Serie A can see it shining in the sky. It is possible. If I could, they can."

After six years of consistent success Sannino left Siena to join Palermo in the summer of 2012, and the run abruptly ended. He was sacked after only three games, reappointed less than six months later, and then resigned last summer to join Chievo, who sacked him last November after one victory in their 12 games. "I developed a system, a kind of 4-4-2, and everywhere I used this system and I had success," he says. "And then I got to Serie A, and learned a big lesson. Until then I knew that if I prepared my teams well, I could always win. In Serie A, I learned that other teams would always be better. The gap was too big."

As it happens the one victory Chievo achieved under his guidance came against Udinese, the Italian club owned by the family that also controls Watford. When Zola resigned in December, having followed last season's run to the play-off final with little but disappointment, Sannino was installed in three days. "The dream of every coach in Italy is to spend just one day working in England," he says. "When I got the call, I had no doubt. I accepted immediately, and I left. Since that call, I have forgotten about Italy. My career there does not matter. Here, nobody knows who I am. I come here, humble, quiet, but I want to show, on the pitch, who I really am."

Watford have not had a huge upturn in fortunes since the arrival of the Italian – they have drawn four out of six league games – but Sannino already professes himself besotted with the English game and cannot wait to take on Manchester City on Saturday. "It's beautiful. It's like a duel, every match, from the first minute to the last," he says. "In Italy, if you play a team from the bottom of the league you will probably win. Here you know you must fight. This is a beautiful thing. Here you have the FA Cup; in Italy we have the Coppa Italia. The difference is that in Italy, from the start you know how it will end. The best eight teams go straight into the last 16, and the strongest side always plays at home. Last year Wigan won the Cup and were relegated. This year Sheffield United, a team near the bottom of League One, beat Aston Villa, a team from the middle of the Premier League, away from home!

"In Italy it could never happen. It's just impossible. The spirit of English football is all there, in the FA Cup. It is very difficult for the small clubs to win, but they always have a chance."

If England really is the home of the underdog, Sannino and his brilliantly improbable CV might have landed in their perfect destination.