The 1903 Pocket Hammer was an effort by Colt to adapt the Model 1902 pistol for better civilian sales. They cut the barrel down from 6 inches to 4.5, and used the 7-round magazine and rounded grip frame of the 1902 Sporting model. Production began in 1903, and ran until 1929, when the .38 caliber version of the 1911 was introduced to replace both he Model 1902 and the 1903 Pocket Hammer.

This was never a particularly popular model, with just under 31,000 made in the course of 26 years of production. It was a neither-fish-nor-fowl sort of gun that competed against both the Colt 1908 Pocket Hammerless as a concealable pistol and against the Colt 1911 as a service pistol. On top of that, it was based on the obsolete mechanical system from the Model 1900, which had the possibility of the slide coming off the back of the gun if the slide wedge broke, and offered neither a slide stop nor any safeties (neither manual nor magazine).