The 5906 features a traditional double-action/single-action trigger and a 14-round staggered-column (double stack) 9x19mm magazine.
The 5906 is constructed entirely from stainless steel and is thus extremely resistant to harsh weather conditions. The firearm was factory-shipped with a magazine disconnect feature designed to deactivate the trigger if the magazine is not fully inserted. This is nearly unique since it is a double action design. The 5906 comes standard with either a 10 or 15 round magazine. Other features include a pinched barrel designed for tighter slide lock-up, ambidextrous safety levers, spur hammer, a one-piece Xenoy polymer wrap-around grips with either a curved or straight back strap, and a choice of either low-profile Novak 3-dot sights available in either fixed or fully adjustable for windage and elevation. Like most third generation Smith and Wesson semi-automatic pistols, the 5906 features a combination safety lever and decocker mounted on the slide, a plunger type firing pin safety, a magazine disconnect to meet the needs of law enforcement agencies and a pin mounted, pivoting spring actuated external extractor. The 5906 design is famous for its "finger-step" squared trigger guard that is similar to that of a Lionheart LH9. The distinctive trigger guard was later changed to a similar round trigger guard for ease of production because the pistols had recently become popular with law enforcement and the company needed to make pistols faster. The first generation Smith & Wesson semi-auto pistol designations consist of two digits, such as Smith & Wesson Model 39 and Model 59. Second generation pistols are designated by three digits; these include the Model 459, Model 559, etc. Many second generation designs were eventually upgraded with various improvements, thus becoming the third generation pistols; these are identified by the addition of a fourth digit to the second generation model number: 5903, 5904, 5905, 5906, etc. The most common variant of the 5906 was the 4506, which was also popular with law enforcement such as the LAPD. It was produced from 1988 to 1999. Other variants of the 5906 include the 1006, which was chambered for 10mm Auto and designed for the FBI, the 4006, which was primarily targeted for law enforcement, and the 6906, a double action only compact version of the 5906, which was designed for concealed carry and to be a backup pistol for law enforcement. Soon versions of the 5906 were developed that had an aluminum frame, the 5904. Unfortunately, the 5906 is nevertheless being replaced by lighter, polymer-framed models from Glock, Heckler & Koch, SIG Sauer as well as Smith & Wesson's own M&P line of polymer framed handguns in both 9mm and .40 calibers. The 5906 and its third generation variants were manufactured from 1989 to around 2011, when they were all discontinued so production could focus on the M&P series. Many fans of the weapons have called for them to be reintroduced.