The experienced attacker reached the milestone during Wednesday's Copa del Rey win over Alaves, and says he will always remember his most significant strikes
The 30-year-old has scored 40 times for Sporting, 40 more for Zaragoza, then 129 with Valencia, and now 39 at Barcelona, while netting 53 goals for Spain's national side.
"The 300 goals I have to my name now make me realise that I have done well over the years. It makes me proud to have scored this much and to have achieved so many goals," the Spain international was quoted as saying by AS.
"The goals you remember can be the ones that were beautiful or that were difficult. I always think about the one with my head, because those are the most difficult ones for me.
"I also have fond memories of the goal with Valencia against Deportivo, when I scored from midfield. And of course the one for Barcelona at Wembley in the Champions League."
Villa netted his 301st goal only minutes after reaching the 300 landmark.