The TSSAM was designed as a high precision stealthy missile for use at standoff distances, but poor management of the project resulted in rising costs.

Late that year, two missiles failed tests and the project was delayed for three months before completing development in April 2003.

[17] On 27 August 2009, David Van Buren, assistant secretary of the Air Force for acquisition, said that there would be a production gap for the JASSM while further tests were held.

[20] Meanwhile, the United States Navy had originally planned to acquire 453 AGM-158 missiles[21] but instead pulled out of the program in favor of retaining the proven AGM-84H/K SLAM-ER.

JASSM was selected over the SLAM-ER after the European Taurus KEPD 350 withdrew its tender offer, despite the KEPD 350 being highly rated in the earlier RFP process, due to their heavy involvement in the series preparation for the German Air Force, their troop trials in South Africa and their final negotiations with the Spanish Air Force which finally led to a contract.

[19][needs update] In September 2021, Australian Prime Minister Scott Morrison announced that Australia would acquire the JASSM-ER for the RAAF's F/A-18F Super Hornet and F-35A fighters.

However, in February 2007 the United States declined to sell the missiles, while agreeing to proceed as planned with other modernization efforts (the so-called Mid-Life Update 2, or MLU2).

It makes the enemy pause and think twice about aggressive action, because it provides precision strike of a wide range of valuable targets.

[32][33] In 2014, Poland requested US Congressional approval for the purchase of the AGM-158 JASSM to extend the deep penetration strike capabilities of their F-16 Block 52+ fighters.

[34][35][36] The missiles are expected to enter operational service in 2017, and Poland is contemplating an additional purchase for the long-range JASSM-ER version.

The contract includes 140 JASSMs for Finland, Poland and the US, 140 JASSM-ER missiles for the US, and data, tooling and test equipment.

[40] In its 2019 Mid-term Defense Program [ja], the Japanese government introduced a plan to purchase JASSM-ER and the AGM-158C LRASM for use in its F-15J fleet.

[43][44] The US Air Force studied various improvements to the AGM-158, resulting in the development of the JASSM-Extended Range (JASSM-ER), which received the designation AGM-158B in 2002.

Other possible improvements were studied but ultimately not pursued, including a submunition dispenser warhead, new types of homing head, and a new engine giving ranges in excess of 620 mi (1,000 km).

[59] In November 2019, the Air Force retired the AGM-86C/D air-launched cruise missile, a conventional warhead-equipped version of the nuclear-tipped ALCM, with its role replaced by the JASSM-ER.

Future variants are also under development, the AGM-158B-3 will further upgrade the GPS receiver with M-Code capabilities and the AGM-158D will enhance performance with new wing and chine designs, the integration of a line of sight and beyond line of sight Weapon Data Link (WDL) for post-launch retargeting capability, and software updates for increased survivability.

[69] In 2020 and 2021, the Air Force Research Laboratory and Lockheed developed and tested Rapid Dragon, a palletized multiple AGM-158 launcher module to be airdropped by C-130 or C-17 cargo planes as a low cost method of rapidly providing a surge of mass fired JASSMs using unmodified airlift assets.

[74][75][76] In 2018 the AGM-158 XR was designated as AGM-158D JASSM-D.[77] The JASSM was first employed during the 14 April 2018 missile strikes against Syria during the Syrian Civil War.

Two B-1 Lancers fired a total of 19 JASSMs as part of strikes against three Syrian government alleged chemical weapons targets.

[81] According to Russian state media, two missiles that failed to detonate were found by the Syrian Arab Army and transferred to Russia on 18 April for study – no evidence of this claim has been provided;[82] initial reports had stated JASSM-ER missiles were used, but it was later clarified that baseline JASSM models were employed.

[83] On 27 October 2019, at the end of the Barisha raid to capture or kill Abu Bakr al-Baghdadi, the then-leader of the Islamic State of Iraq and the Levant (ISIL) terror organization, a number of AGM-158B missiles were used to completely level the compound where the raid took place, marking the second time the missile has been used in combat.