The King’s Gambit isn’t seen much these days at any level of chess though playing it can help develop certain skill sets such as a feel for the attack. The only World Champion to play it much was Boris Spassky and meanwhile lesser known King’s Gambiteers such as English GMs Mark Hebden and Joe Gallagher have given it up. So it currently has no champion.
There is a fun story about how Gallagher started playing this opening. I understand that he won some money from Mark Hebden at poker but then took King’s Gambit lessons in lieu of cash. This resulted in Gallagher becoming a fearsome exponent of this opening and he later wrote an excellent book about it.
Anyway, here’s Boris Spassky using this opening against very serious opposition, the then World Champion Anatoly Karpov. And White had very good chances before letting Black off the hook and then finally winning in the time scramble.