The first assignment of the B-32 began when General George Kenney the commander of Allied air forces in the South West Pacific Area, and commander of the U.S. Fifth Air Force, traveled to Washington D.C. to request B-29s. Since priority had been given to strategic bombing by the B-29, Kenney's request was denied, after which he requested the B-32. Following a demonstration, the Army General Staff agreed that Kenney could conduct a combat evaluation, and a test schedule of eleven missions was set up, followed by a plan to convert two of the 312th Bomb Group's four Douglas A-20 Havoc squadrons to B-32s. Project crews took three B-32s to Clark Field, Luzon, Philippine Islands in mid-May 1945, for a series of test flights completed on 17 June. The test crews were impressed with its unique reversible-pitch inboard propellers and the Davis wing which gave it excellent landing performance. However, they found a number of faults: the cockpit had an extremely high noise level, a poor instrument layout, the bombardier's vision was impaired, it was overweight and the nacelle design resulted in frequent engine fires. The three test B-32s were assigned to the 312th BG's 386th Bomb Squadron. On 29 May 1945, the first of four combat missions by the B-32 was flown against a supply depot at Antatet in the Philippines, followed by two B-32s dropping sixteen 2,000 lb (910 kg) bombs on a sugar mill at Taito, Formosa on the 15th of June. On 22 June, a B-32 bombed an alcohol plant at Heito, Formosa, with 500 lb (230 kg) bombs, but a second B-32 missed flak positions with its 260 lb (120 kg) fragmentation bombs. The last mission was flown on 25 June against bridges near Kiirun in Taiwan.
The testing missions were mostly successful, and, in July, the 386th Bomb Squadron completed its transition to the B-32, flying six more combat missions before the war ended. On 13 August, the 386th BS moved from Luzon to Yontan Airfield on Okinawa and flew mostly photographic reconnaissance missions. The missions were intended to monitor Japan's compliance with the cease fire and to gather information such as possible routes occupation forces could take into Tokyo. In addition, Rudolph Pugliese, who was the 386th's assistant intelligence officer, said in 1997 that "the photo-recon missions were also intended to test the fidelity of the Japanese...[adherence] to the terms of the cease-fire." On 17 August, three B-32s in a flight of four were attacked by Japanese flak and fighters. During the two-hour engagement, the Dominators suffered only minor damage and none of their crew were injured. "Though the B-32 gunners later claimed to have damaged one fighter and 'probably destroyed' two others, surviving Japanese records list no losses for that day or next." Based on the Japanese action on the 17th, U.S. commanders felt that it was important to continue the reconnaissance missions over Tokyo so they could determine if it was an isolated incident or an indication that Japan would reject the cease-fire and continue fighting.
On 18 August, four Dominators were given the task of photographing many of the targets covered on the previous day; however, mechanical problems caused two to be pulled from the flight. Over Japan, a formation of 14 A6M Zeros and three N1K2-J Shiden-Kai fighters (as is often the case, Shiden-Kai is described as Ki-44 Tojo, but it may be a misunderstanding of the crews) attacked the remaining two U.S. aircraft. Saburo Sakai, a Japanese ace, said later there was concern that the Dominators were attacking. Another Japanese ace, Sadamu Komachi, stated in a 1978 Japanese magazine article that the fighter pilots could not bear to see American bombers flying serenely over a devastated Tokyo. The B-32 Dominator Hobo Queen II was flying at 20,000 ft (6,100 m) when the Japanese fighters took off and received no significant damage. Hobo Queen II claimed two Zeros destroyed in the action as well as a probable Shiden-Kai. The other Dominator was flying 10,000 ft (3,000 m) below Hobo Queen II when the fighters took off. The fighters heavily damaged that Dominator and seriously wounded two crew members. Photographer Staff Sergeant Joseph Lacharite was wounded in the legs (his recovery required several years). Sergeant Anthony Marchione, a photographer's assistant, helped Lacharite and then was fatally wounded himself. Despite the damage it received, the Dominator was able to return to Okinawa. Marchione was the last American to die in air combat in World War II. On 19 August, propellers were removed from all Japanese fighters as per the terms of the cease fire agreement. The last B-32 combat photo reconnaissance mission was completed on 28 August, during which two B-32s were destroyed in separate accidents, with 15 of the 26 crewmen killed. On 30 August, the 386th Bomb Squadron stood down from operations. Production of the B-32 was cancelled on 8 September 1945, and ceased by 12 October.