A seal assembly is for a closure element of a valve assembly including a valve body with a flow passage and an annular seat extending about the passage, the closure element being linearly displaceable along a central axis and including a cylindrical body. The seal assembly includes an outer seal including an annular body formed of a polymeric material and having a centerline, an inner circumferential surface defining a seal bore, an outer circumferential surface, and opposing first and second axial ends, the first axial end having a generally radially-extending, annular sealing surface sealingly engageable with the valve seat. An inner connector includes a generally annular body formed of a substantially rigid material and disposed at least partially within the seal bore, the connector body having an inner circumferential surface frictionally engageable with the valve body outer surface to couple the seal with the closure element.