Lasse was born on 17 February 1918 in Rawitsch in the Province of Posen within the German Empire, present-day Rawicz, Poland.

[3] World War II in Europe had begun on Friday, 1 September 1939, when German forces invaded Poland.

Following the decision by Adolf Hitler to halt work on the aircraft carrier Graf Zeppelin,[4] II./186 (T) was redesignated and became the III.

Gruppe was withdrawn from this theater of operations and relocated to Döberitz where it was tasked with fighter protection of Berlin.

[7] In November, JG 77 was ordered to the English Channel to continue fighting the Royal Air Force (RAF) in the aftermath of the Battle of Britain.

Gruppe was moved to Bucharest and was located in the sector of Heeresgruppe Süd (Army Group South).

[15] That evening, the pilots and ground crews were briefed of the upcoming invasion of the Soviet Union, which opened the Eastern Front.

[16] Engaged in aerial combat with Mikoyan-Gurevich MiG-3 fighters, Lasse was killed in a mid-air collision with his wingman, Feldwebel Robert Helmer, on 8 October 1941.

While Helmer nursed his damaged aircraft back, Lasse's Bf 109 F-4 (Werknummer 8475—factory number) crashed near Armiansk.