In the years leading up to the Civil War, a floating dry dock, steam sawmill, gas fixtures, and housing for senior officers were added to the site. The yard quickly expanded its workforce to include 1700 shipyard workers to keep production running smoothly. But production did eventually wane, and in 1876, the yard took on the new name of League Island Navy Yard and the company began a program of renovation to improve its dwindling status. The plan worked, and by 1903, the yard became the headquarters of the new Fourth Naval District.
The shipyard expanded greatly during WWI. Additional facilities included barracks, Shipways 2 and 3, a chemical laboratory, a 1000-foot Dry dock, a 350-ton hammerhead crane, a POW camp for German ship crews, and the Naval Aircraft Factory.
Between 1937 and 1941, the yard constructed the carriers Princeton, Antietam, and Valley Forge, the battleships New Jersey and Wisconsin, and the destroyers Butler and Gherardi. The company assembled both these ships in a record-setting five months. During this period, the yard produced 53 ships total, and it repaired 574 more. Shipyard workers numbering 45,000 found employment on these projects. Repair and overhaul of ships with complicated electronic and combat systems became the yard’s specialty after WWII.
During the 1980s, the yard focused on the Service Life Extension Program, a system centered on rebuilding outdated aircraft carriers. This program gave the yard a few more good years, and in 1991, the yard finished its work on the USS Kennedy under the permission of the Defense Base Closure and Realignment Commission. The shipyard finally closed on September 27, 1996, about a year after the completion of the USS Kennedy project.