A portable electronic device may have a sealed connector secured within a device housing. The sealed connector may have a metal shell. A plastic contact housing may be insert molded within the shell. Conductive signal contacts may be laterally spaced in the contact housing. An elastomeric gasket may be assembled or compression molded onto the metal shell. Left and right metal brackets may be welded onto the metal shell to moisture-seal latch windows. A water-resistant sealing layer may be attached to the bottom plate of the metal shell to moisture-seal alignment rail windows. The sealed connector may be pressed against the device housing to place the gasket in a compressed state. The connector may be secured to the device housing by screwing down the metal brackets to a circuit board assembled within the housing while the gasket is in the compressed state.