MD 63 began to take its modern form in the late 1950s. The MD 63 designation was extended east from Spielman to MD 65 in Fairplay in 1957. MD 63 was also extended north past US 11 and replaced MD 398 between Williamsport and Cearfoss. The state highway was extended north from Cearfoss to the Pennsylvania state line in 1958. Reconstruction and relocation of the highway from the northern limit of Williamsport to a short distance north of US 40 in Huyett began in 1957. The realignments bypassed what are now Honeyfield Road, Celeste Drive, Kemps Mill Road, and Rock Hill Road north of Williamsport and Huyett Lane in Huyett. The Williamsport–Huyett project included a bridge over the Western Maryland Railway that was completed in 1959. MD 63 was later expanded to a four-lane divided highway concurrent with the construction of its interchange with I-70, which opened in 1967 along with the stretch of I-70 from MD 68 to I-81.