Lech Walesa isn't a football fan but he has no doubt as to its power, which is why he is an enthusiastic ambassador for Euro 2012. The theory goes that the frequent German and Russian invasions and then the years of communism had bred negativity and a cynicism: Polishness became about resistance, about standing up to, perhaps even undermining the establishment. Now, with independence, the challenge is to find a positivity, to learn how to create rather than destroy.

The investment in infrastructure Poland has seen over the past couple of years would probably have happened anyway over the next decade or so, but Euro 2012 provided a focus and an impetus. Drawing up to half a million visitors (although that official figure does seem highly optimistic) over the next month should provide a boost both in terms of finances and reputation. The greatest impact, though, may be symbolic.

The Euros, as the biggest international event staged in Poland since the collapse of communism, offer the best opportunity yet to show that a new, proactive nation is emerging. And that means interaction and engagement with the rest of the continent. "The problem is that we have no choice," Walesa said. "We must thread Europe together. We must learn from each other. Poland could not afford to organise the Olympic Games so we must do everything we can to get to know each other in the best possible way. Poland needs more self-confidence and we all need more European unity. It is a political world and sport is not a part of that but it will help us a lot."

I met him in his office in Gdansk. He is 68 now, his hair white and the famous moustache a little thinner than in its bristling heyday, but he still radiates an extraordinary energy. In the early 80s, as the Solidarity movement he led from the shipyards began to threaten the communist government, football provided a network for his movement to spread. "We had to do our best to get the revolution going," he explained. "We had to build up the foundations to get the fight on. Sport was just one of the ways we met each other and found out how much we had in common. We became much closer thanks to football and we relied on these relationships. Football was very important."

The local club was Lechia, supported by most in the shipyards although they were a third-division side. In 1982-83, though, they went on an extraordinary Cup run. As though carried by the mood of optimism and resistance around Gdansk, they beat Widzew Lodz, Slask Wroclaw and Ruch Chorzow on their way to the final. There they met Piast Gliwice and beat them 2-1 to complete a remarkable triumph. It would have been a stunning success in any environment; in the Poland of the time it was genuinely historic — a symbol of what underdogs could achieve against much more powerful opponents. "For us it was a victory achieved by a great club," Walesa said, "but others saw us as David fighting and winning against Goliath."

Matches had become rallying points for dissent, the terraces an arena where the secret police no longer had control. "We needed to show the Communist Party that they were not the only power in Poland at that time," Walesa said. "They always tried to keep us down and marginalise us. So we had to unite. They felt really paralysed by seeing how united we were during football matches."

The Cup victory also offered a unique opportunity. So paranoid had the authorities become that all matches from the 1982 World Cup, in which Poland finished third, were broadcast with a few minutes delay so that any pro-Solidarity banners could be blacked out. Lechia had qualified for the Cup-Winners' Cup, in which they were drawn against Juventus.

They knew that in Italy, the game would be screened live and that the communist authorities could do nothing to edit the pictures shown.

This was a chance to demonstrate to the world just how much support Walesa and Solidarity had, to make a gesture far greater than a few banners in Spain.

Lechia lost the first leg 7-0 in Turin, but for what Walesa had planned that didn't matter. He had been released from jail a few months earlier and was still followed everywhere by the secret police.

On the day of the second leg, which Juve won 3-2, he gave his mentors the slip and snuck into the stadium. Midway through the first half, he emerged on the terrace, an act of defiance recognised by rapturous cheers. "I was at the game," he said. "The stadium was packed. The crowd shouted the name of Solidarity. It sounded really perfect. We really did upset the communists and all the secret police. Yes, it was a great moment of that time."

A month later, Walesa won the Nobel Peace Prize and, in 1990, he became the first democratically elected president of Poland. He may not be particularly keen on the game, but he has no doubt as to the part it played in his challenge to Communism, or how important Euro 2012 is in shaping Poland's future.

In April 2011 Jonathan Wilson visited Poland to examine the efforts to drag football into the 21st century in time for Euro 2012 for a Guardian Focus podcast. Listen to it here