1940, "wedge-heeled shoe," from wedge (n.) + -ie. The underwear prank so called by 1970s, from the effect it gives the victim.
Entries linking to wedgie
wedge n.
Old English wecg "a wedge," from Proto-Germanic *wagjaz (source also of Old Norse veggr, Middle Dutch wegge, Dutch wig, Old High German weggi "wedge," dialectal German Weck "wedge-shaped bread roll"), of uncertain origin; perhaps related to Latin vomer "plowshare." From 1610s in reference to other things shaped like a wedge. Of women's shoes or shoe-heels, from 1939. Wedge issue is attested from 1999.
-ie
alternative spelling of -y; now mostly of -y (3), but formerly of the others as well.