Although sometimes assumed to have been named after Commodore Stephen Decatur, a War of 1812 and the First Barbary War and the Second Barbary War naval hero, the school is in fact named after the USS Decatur, a ship named for Stephen Decatur that assisted settlers during the 1856 Battle of Seattle.

Within the framework of this concept, there were few permanent walls built in the school's original structure.

Decatur is part of the Olympic Division of the 4A North Puget Sound League in Washington's West Central District.

Recent team finishes in State Championships include: Other sports are Football, Baseball, Basketball, Cross Country, Gymnastics, Fastpitch Softball, Volleyball, Soccer, Wrestling and Golf.

Decatur's main rivals are the Federal Way Eagles and the Thomas Jefferson Raiders