After attending hotel management school, completing military service and international engagements in the United States, France, and Italy, he took over his parents' business, Der Seehof, in Goldegg am See in 1996.

As a restaurateur, Sepp Schellhorn was actively involved in representing the interests of hoteliers; he was President of the Austrian Hotel Association from 2003 to 2013.

[2] In 2017, Schellhorn published the Generationenkochbuch (German: Generational Cookbook) with his mother and son, featuring recipes from Alpine cuisine.

In the first year after the election, Schellhorn held the distinction of being the deputy with the lowest attendance rate, being present for only 23.6% of parliamentary votes.

[8] After Beate Meinl-Reisinger became federal chairwoman of NEOS in October 2018, Schellhorn was elected deputy chairman, alongside Nikolaus Scherak.