The first team in Washington, the Potomac Club, was formed in the summer of 1859, and the Nationals were formed in November of the same year; both teams consisted mostly of government clerks. The two teams practiced in the backyard of the White House and played each other in the spring of 1860; the Nationals consistently lost to the superior Potomacs, but the latter disbanded on the outbreak of the Civil War while the Nationals kept playing, and by the end of the war were "solidly in the esteem of Washington fans, with the club's shortstop, slight, 23-year-old Arthur Pue Gorman, the darling of the spectators. Young Gorman quickly rose to stardom on the not-too-brilliant Nationals." (Gorman later became a U.S. Senator from Maryland and a power in the Democratic Party in the late 19th century).
In the summer of 1865 the Nationals invited the Philadelphia Athletics and Brooklyn Atlantics, two of the major teams of the era, to Washington, losing to the former 87–12 and to the latter 34–19, before 6,000 spectators, including President Johnson. They "jealously guarded their amateur status by refusing all payments, including travel expenses."
By 1867, the Nationals were much improved, and the new national network of railroads prompted them "to do the previously unthinkable by becoming the first Eastern team to venture west of the Alleghenies." They defeated the best the locals had to offer, crushing Columbus 90–10, the Cincinnati Red Stockings 53–10, and the Cincinnati Buckeyes 88–12, beating Louisville, Indianapolis, and St. Louis as well before falling to the Rockford Forest Citys (with future Hall of Famer Albert Spalding) 29–23. The Nats ended the road trip the next day by beating the Chicago Excelsiors 49–4. The "considerable expenses" of the tour were made possible by generous sponsors and "by the indulgence of the Treasury Department."