Lombard perpetrated mass murder in the Holocaust, serving as commanding officer of the 1st Regiment of the SS Cavalry Brigade during the German invasion of the Soviet Union.

After his father's death in 1906 he visited his relatives in the United States in 1913, where he graduated from high school and started studying Modern Languages at the University of Missouri.

That in case of resistance, commander Lombard gave orders that his soldiers hunt and kill any non-German boy and man between the ages of 17 and 60 years.

In the end of July 1941 Lombard was commander of a mounted detachment of the 1st SS Cavalry Regiment deployed east of Brest-Litovsk, where he allegedly first used the term ”Entjudung” (De–jewification).

This action became known as the Pripyat Marshes massacres (German: "Pripiatsee"); it was conducted by the combined SS and Wehrmacht forces in July and August 1941 as the "systematic combing" of the area for Jews, 'partisans' and Red Army stragglers.

[7] Historian Peter Longerich notes that most orders to carry out criminal activities such as the killing of civilians were vague, and couched in terminology that had a specific meaning for members of the regime.

Fegelein's final report on the operation, dated 18 September 1941, states that they killed 14,178 Jews, 1,001 partisans, 699 Red Army soldiers, with 830 prisoners taken and losses of 17 dead, 36 wounded, and 3 missing.

Talks presented included the evaluation of Soviet 'bandit' organisation and tactics; why it was necessary to execute political commissars immediately upon capture; and the connection between Jews and partisans.

The conference, while ostensibly an 'anti-partisan training', was in fact a means 'to promote the annihilation of Jews for racial reasons', as a post-war West German court put it.

[20] On 15 January 1944, Lombard was appointed Chief of Staff of Stossgruppe von dem Bach, a rapid deployment assault unit under the command of Bach-Zalewski.

Through March 1944, the unit conducted defensive operations and counter-strokes against both partisan formations in the rear and the Red Army forces trying to encircle the city.

During the Kovel operations, SS troops and police allegedly perpetrated atrocities in the surrounding area, shooting civilians and burning down villages.

In 1955 he returned to West Germany after Chancellor Konrad Adenauer negotiated the release of the remaining German POWs and war criminals from the Soviet Union.