Wineinger was a two-time Midwest Classic North Conference Player of the Year and a four-time all-conference selection at Lake Country Lutheran High School. The four-time varsity MVP earned second-team all-conference honors as a freshman and was a first-team pick in each of her final three seasons.

A three-time team captain and three-time selection to the Badger Region High Performance Team, Wineinger posted 241 kills (3.6 kpg) as a freshman and logged 388 kills (3.9 kpg) as a sophomore while leading the Lightning to their first regional championship title in school history. She established a single-match record in aces with 14. Wineinger set a Lake Country Lutheran single-season record with 395 kills (4.4 kpg) as a junior and averaged 4.6 kills per game as a senior.

Wineinger earned Milwaukee Journal Sentinel honorable mention all-area honors as both a junior and senior.

A member of the National Honor Society, Emily is the daughter of Tony and Sue Wineinger, of Hartland, Wisconsin.