Cornish menganyam pendidikannyabersekolah di [[Sekolah Westminster|Westminster School]] di [[Central London|London]], dimana Cornish bertemu dengan Adam Buxton juga Louis Theroux . <ref>{{Cite news|last=Hogan|first=Michael|title=Forget Christmas TV: Adam and Joe's 20th anniversary reunion podcast is the best present you'll get in 2016|url=https://www.telegraph.co.uk/comedy/comedians/forget-christmas-tv-adam-joes-20th-anniversary-reunion-podcast/|access-date=3 June 2017|publisher=The Telegraph|date=25 December 2016}}</ref> Di usianya yang ke 18, Cornish melanjutkan jenjang pendidikannya di Sekolah Film Bournemouth . <ref>{{Cite web|url=http://www.bbc.co.uk/6music/shows/adam-and-joe/biography/|title=Adam & Joe's Biography|publisher=BBC Radio 6 Music}}</ref>
