[1] Petkov began his career at Cherno More Varna and joined Heart of Midlothian at the age of 16 in June 2016, signing a three-year contract.
[2] On 22 July 2017, Petkov made his first-team debut, replacing John Souttar during a 3–0 League Cup victory over East Fife at Tynecastle Park.
On 19 January 2018, Petkov joined Scottish League Two side Berwick Rangers on loan until the end of the season.
[5] On 6 July 2023, after a two-year stint at Arda Kardzhali, Petkov joined Polish side Śląsk Wrocław on a one-year contract, with an option for another two years.
[7] He earned his first cap for the senior national team on 26 March 2022, coming on as a substitute during the second half in the 1–2 loss against Qatar in a friendly match.