He is known for his roles as Wolfgang on the Nickelodeon comedy series The Thundermans (2015–2018) and Dr. Levi Schmitt on the ABC medical drama Grey's Anatomy (2017–present).

Whilst in Columbus, Borelli also performed in more than a dozen shows with the Columbus Children's Theatre which included roles in Cheaper by the Dozen; The Lion, The Witch and The Wardrobe; Wiley and the Hairy Man; and Holes.

[2] Borelli publicly came out as gay on his personal Instagram in November 2018, moments after the airing of the sixth episode of Grey's Anatomy's fifteenth season, in which his character, Dr. Levi Schmitt, also came out.

[3] In March of 2022, Borelli posted a picture of him and Chase Williamson, a professional photographer, attending the Elton John AIDS Foundation's 30th Annual Academy Awards Viewing Party to his Instagram page.

That same year, it was announced that Borelli would be playing intern Dr. Levi Schmitt on Grey's Anatomy.