Lazek made his professional debut in June 1932, winning a four-round points decision against Sandor Kunstzler.

Following two successful defences of his title, against Rienus De Boer and Emilien Ollivon, Lazek was beaten by Gustave Roth via a fifteen rounds points decision in September 1936.

Having remained undefeated over his next nine bouts, Lazek was able to challenge the EBU heavyweight champion, Arno Kölblin, in March 1938.

In March 1939 Lazek suffered a fifth round knockout loss against Adolf Heuser, bringing his title reign to an end.

Although Lazek never fought for a European championship again, he won the German BDB heavyweight title in November 1940 and successfully defended it once before losing for a second time to Heuser.