He was active in many local Polish-American organizations and would make campaign speeches both in English and in the Polish language.

In 1938, Wasielewski unseated incumbent Congressman Raymond Joseph Cannon in the Democratic primary for Wisconsin's 4th congressional district, but was narrowly defeated in turn by a former incumbent, Republican John Schafer, with 33,559 votes (31.40%), to Schafer's 34,196 (32.00%), Progressive Paul Gauer's 30,817 (28.84%), 7,498 votes (7.02%) for Cannon (who ran as an independent) and 794 votes (0.74%) for a Union Party candidate.

Wasielewski was an interventionist (supported American entry into World War II) in a largely isolationist state.

As a result, they both lost to Republican John C. Brophy, who drew 49,144 votes to Bobrowicz' 44,398, Wasielewski's 38.502, and Socialist George Helberg's 2,470.

His papers are owned by the Wisconsin Historical Society, and are housed in the University of Wisconsin–Milwaukee's Golda Meir Library Archives Department, in the Milwaukee Area Research Center.