Design work on a new family of pistols commenced in September 1989, focused primarily on the United States commercial and law enforcement markets.

USP prototypes participated in rigorous testing alongside H&K's entry in the Offensive Handgun Weapon System (OHWS) program requested by the U.S. Special Operations Command (USSOCOM), which would later result in the Mk 23 Mod 0.

The USP prototypes were then refined in 1992, based on input from the OHWS trials, and the design was finalized in December of the same year.

In contrast to the P7, P9S, and VP70Z designs, the USP uses a more conventional Browning-style cam-locked action, similar to that used in the Hi-Power, but with a polymer frame.

This rather conventional lock-up system has a large rectangular lug over the barrel's chamber that rides into and engages the ejection port cut-out in the slide.

After 3 mm (0.12 in) of unrestricted rearward travel, the projectile leaves the barrel and the gas pressures drop to a safe level.

This tapered surface produces a camming action which assists in positive lock-up in the presence of heavy fouling and debris.

Designed primarily to reduce wear on the pistol's components, the system also lowers the peak recoil forces felt by the shooter.

Unlike similar systems employed in other pistols, the USP design does not incorporate a hydraulic damper and requires no maintenance.

Using a similar recoil reduction system, the H&K Mk 23 pistol fired more than 30,000 high pressure (+P) cartridges and 6,000 proof loads without damage or excessive wear to any major components.

MILSPEC environmental tests were conducted in high and low temperatures, in mud, immersed in water and in salt spray.

The barrel was successfully cleared with only minor structural deformation and continued to produce consistent groups when test fired for accuracy.

The recoil reduction system is not present on the USP Compact models, which instead use a simple polymer bushing as a buffer to reduce slide on frame impact.

[6] Internal metal parts, such as springs, are coated with a Dow Corning anti-corrosion chemical to reduce friction and wear.

[4][6] By using a modular approach to the internal components,[3] the control functions of the USP can be switched from the left to the right side of the pistol for left-handed shooters.

[6] In addition to a wide selection of trigger/firing modes, the USP has an ambidextrous magazine release lever that is shielded by the trigger guard from inadvertent actuation.

An extended slide release lever is positioned to allow easy operation without changing the grip of the shooting hand.

Due to the smaller size of the frame, magazines for the Compact variant may have a handgrip extension to better accommodate the shooter's hand.

A unique characteristic of the USP Tactical is that the barrel is left-hand threaded (counter-clockwise to tighten), which makes the pistol incompatible with suppressors designed for the MK23 Mod 0.

Features include an extended, threaded O-ring barrel with polygonal bore profile and suppressor height sights, which may limit the use of holsters designed for standard USP Compact pistols.

The USP has an accessory rail at the front of the frame for attachments of aftermarket equipment such as laser sights and weapon lights.

Peak force shock on competing .40 caliber polymer and metal framed pistols was around 5,000 newtons (1,100 pounds-force).

The primary benefit of low peak shock is a decrease in wear and tear on pistol components, a great concern with the +P cartridge in 9 mm, .40 S&W, and .45 ACP.

[14][15] In 1998, the H&K USP Compact with the LEM trigger action, in .40 S&W, was adopted by the United States Immigration and Naturalization Service as the duty sidearm for its Special Agents and plainclothes officers.

[16] On August 24, 2004, SIG Sauer and Heckler & Koch/HK Defense won major pistol contracts with the United States Department of Homeland Security.