The 17th Observation Squadron (Light) was constituted on 5 February 1942 and activated on 2 March 1942 at Providence, Rhode Island with Air Force Combat Command.

The 17th was relocated to Laurel Army Airfield, Mississippi, on 31 March, where it was redesignated as the 17th Reconnaissance Squadron (Bombardment) and began training on the North American B-25 Mitchell medium bomber, in preparation for combat in the South-West Pacific Area.

[8] On 27 February, when the Battle of Los Negros began with an Allied landing on that island, three B-25s from the squadron sortied to provide a smoke screen for the invasion beaches if required, but were not used due to cloud cover.

[10] The squadron conducted daily search missions along the coast from Finschhafen to Geelvink Bay, blockading the port of Hollandia and inflicting heavy losses on its shipping along with other Allied air and naval assets.

[12] Following two days of bad weather, twelve B-25s from the 17th Squadron successfully dropped food and supplies to the 21st Infantry, who had made the main landing at Hollandia, at Dazai on 26 April.

[14] The squadron's aerial photography during that week revealed that the Sarmi area was too heavily manned by Japanese to build an airfield there.

[17] The 17th's aircraft provided direct air support to the troops on Biak when called upon, but were endangered by trigger-happy friendly anti-aircraft gunners.

Three aircraft, including Tennille's plane, were shot down, and the remainder were so badly damaged by anti-aircraft fire that the entire 17th Reconnaissance air echelon was sent back to Finschhafen two days later to reform.

[5] On 2 July, the squadron sent three missions of B-25s to provide air support to the invasion troops in the Battle of Noemfoor, bombing and strafing Japanese positions.

[21] On 20 August, the squadron's B-25s conducted low level photography over the Talaud Islands, covered by a bombing raid from the 345th Bombardment Group.

It flew reconnaissance missions over Japan to assess the results of Allied bombing raids, locate prisoner of war camps, and photograph Japanese troop positions.

It was equipped with Fairchild AC-119G Shadow gunships[7] and replaced the 71st Special Operations Squadron, which relocated to the United States for inactivation.

By the end of June, the squadron, commanded by Lieutenant Colonel Richard E. Knie, had trained replacements and begun routine operations.

Due to the pressure on aircraft maintenance, the squadron put in relief from at least one Shadow mission per night in the last half of August.

On 11 October, Shadow 76 was destroyed and six crewmembers killed when it crashed upon takeoff for a mission from Tan Son Nhut, the squadron's first aircraft loss.

[29] A decrease in the number of missions, a decline in enemy activity, and worsening weather slightly changed the "seek and destroy" gunship concept of the first half of the year to a "combat air patrol" role.

[29] During its first six months of operations, the squadron's crews flew 2,000 sorties and 8,000 combat hours, fired 20 million rounds of ammunition, expended 12,000 flares, killed 800 enemy, destroyed 150 sampans, and recorded 800 secondary explosions despite aircraft corrosion and equipment issues, reorganization, and retraining of aircrew and support personnel.

From 3 April to 31 May, the AC-119Gs based at Tan Son Nhut tested a portable UHF receiver for signals transmitted by ground sensors.

[34] Between 10 October and 27 November, the squadron moved more aircraft to Tan Son Nhut from Phan Rang and Phù Cát due to operational needs in Cambodia.

Three gunships and four crews were relocated from Phan Rang to Phù Cát, and air support enabled the Lima Sites to reset defenses in around five days.

Between 12 and 15 December, 32 squadron missions expended 555,800 7.62mm rounds and 128 flares in support of the Cambodian Army defense of Prey Totung.

[39] In late June, after Clark Air Base was closed by the Mount Pinatubo eruption, the squadron commander helped establish a temporary beddown location for the 353d Wing at Kadena.

[42] In February 1993, the 17th SOS was grounded for ten days due to a flying hours reduction caused by budget issues.

[44] In 1994, it deployed crews to the Middle East for Operation Provide Comfort, augmenting personnel at Incirlik Air Base.

[45] In December 1996, the 17th deployed a Combat Shadow crew to San Vito Air Station in support of Operation Joint Guard in the Kosovo War.

The squadron deployed aircraft and personnel to Bangkok in order to aid relief efforts in Operation Unified Assistance.

[46] After the 2011 Tōhoku earthquake and tsunami on 11 March of that year, the squadron deployed to Yokota Air Base to support the relief effort in Operation Tomodachi, returning to Kadena in early April.