[3] Kornvig progressed through the Lyngby Boldklub youth academy, before permanently being promoted to the first team in 2020.

He tested positive for COVID-19 without symptoms on 23 September 2020 ahead of Lyngby's match against FC Nordsjælland.

[4] On 18 January 2021, he signed a contract extension keeping him at the club until 30 June 2024.

[5] He suffered relegation to the Danish 1st Division with the club on 9 May 2021 after a loss to last placed AC Horsens.

[10] After only half a season at Cittadella, Kornvig moved on to Norwegian top-flight club Brann in on 16 February 2024.