Final answer:
Lech Wałęsa was the leader of the Solidarity movement, which significantly contributed to the fall of communism in Poland and led to his presidency in the democratic Poland that emerged.
Step-by-step explanation:
The Polish leader of the independent labor union, Solidarity, was Lech Wałęsa. This movement played a pivotal role in opposing the domination of communism in Poland, originating as an independent trade union in the 1980s. Lech Wałęsa went on to become Poland's president after the fall of communism in the country, signaling a monumental change in Eastern European politics. The Solidarity movement, with its vast membership, was a significant force against the Communist Party, despite initial attempts by the Polish government to suppress it.