The Spielman Road portion of MD 63 was constructed in two segments from Spielman to Downsville and from there to Williamsport in the mid 1910s and early 1930s, respectively. The Greencastle Pike portion of MD 63, which follows a former turnpike, was constructed as MD 398 from Williamsport to Cearfoss in the early 1930s. MD 63 was extended to its present termini, assuming MD 398, and was rebuilt from Williamsport to Huyett in the late 1950s. The state highway was reconstructed along with MD 68 south of Williamsport concurrent with I-81 in the mid-1960s.