Fornalik, 49, has been coach of provincial club Ruch Chorzow for the last three years, leading them to second place in the Polish league last season. He also spent his entire playing career at the club, making 233 appearances.
However, critics say he lacks international experience as he never played for his country and has coached in only a handful of European club games.
"Two years ago the players of the Polish league chose him as the best (league) coach," Polish federation president Grzegorz Lato told reporters as he announced the appointment.
"That means he is well appreciated. I think he is one of the most talented Polish coaches and I hope he will do great job for the national team."
Fornalik has also coached Gornik Zabrze, Amica Wronki and Widzew Lodz.
Previous national coach Franciszek Smuda left after the team's group stage exit from Euro 2012, which Poland co-hosted with its neighbour Ukraine.
Fornalik will be responsible for trying to qualify Poland for the 2014 World Cup in Brazil. They face England, Ukraine, Moldova and San Marino in European Group H.
He has one friendly against Estonia in Tallinn on Aug. 15 to work with the team before they kick off their campaign in Montenegro on September 7.
One of his first decisions will be whether to restore Slawomir Peszko to the squad.
The Cologne winger missed out on Euro 2012 after Smuda, who had a strict policy on alcohol, dropped him in April when the player ended up in police custody in Germany after a night of drinking.
Poland reached their peak when they finished third at the 1974 and 1982 World Cups. They were knocked out in the first round of the 2002 and 2006 tournaments and failed to qualify for South Africa in 2010.