Pistols were typically not issued to enlisted men in the U.S. Army in WWII save for machine gunners, MPs, and senior NCOs. With that being said, many enterprising Joes picked up handguns they found along the way, typically from former enemy stockpiles to augment their M1 Garand, Carbine or Thompson.
GIs with trays of captured Walther P38s
While of course, the guns were valuable as souvenirs, second only to a Gunto sword or HJ dagger, they were also carried and undoubtedly used to one extent or another.
96th Infantry Division moves up Big Apple Hill, scene of intense fighting on Okinawa, April 1945. While his M1 Garand is very much in use, he also sports both a Japanese Nambu holster and an M1911
U.S. Soldier in an M-1943 Field Jacket, armed with an M1 Garand somewhere in the ETO. Besides the bandoliers of .30-06, he has a captured P08 trophy Luger hanging from his belt
Two German soldiers surrender to a USGI armed with his own recently acquired Luger in WWII Europe
US soldier with captured P38 Walther in an Army M7 shoulder holster
Likewise, the British, Canadians and Australians were also captivated with second-hand Axis pistols and were frequently seen carrying them.
Lance Sergeant Earl Henry Scotty McAllister, Argyll and Sutherland Highlanders of Canada, posing with a captured Luger after heavy fighting during the Battle of the Falaise Gap.
Owen SMG-equipped Australian troops examine a captured Nambu Type 14 after the Battle of John’s Knoll–Trevor’s Ridge.
Captured P38 pistols being examined by British soldiers in WWII
Canadian soldier checking out a captured P38 during WWII
CPL Kormendy of The Calgary Highlanders, note his P-38
Poetically, William Joyce, AKA Lord Haw-Haw, was shot in the butt by a British soldier with a captured P-38 while being taken into custody near the Danish border in May 1945.