Robert Lewandowski is eager to make an immediate impact with the Chicago Fire after completing his move to Major League Soccer.

The 37-year-old striker signed a two-year contract with the Fire after deciding not to remain in Europe once his deal with Barcelona expired in May.

"I couldn't imagine myself with a different club besides Barcelona, so we knew the next step would be outside Europe," Lewandowski said Tuesday during his introductory news conference at the club's training facility. "It's not easy to move from Europe to the U.S., but we're very excited. Our lives are changing, and it's a new experience."

Lewandowski leaves Barcelona after four successful seasons, scoring 119 goals in 192 appearances. He helped the Catalan club win three La Liga titles, including last season's championship, as well as the Copa del Rey.

Lewandowski also has played a record 167 international matches for Poland, beginning with a goal on his debut against San Marino in 2008, when he was 20. He is Poland's all-time leading scorer with 89 goals.