Playing an active part in a major finals has eluded Walcott until now as he scored as a substitute and then set up the winner for Danny Welbeck in the 3-2 win over Sweden on Friday night.
Walcott said: "To make my first tournament performance in a high-profile match means so much to me.
"It's been a long time coming and hopefully there will be more to come from me. It certainly whets your appetite.
"It seems only the other day, rather than six years ago, that I was picked to go to the World Cup as a 17-year-old.
"Now to finally play in a major finals is a special moment and one to saviour and remember, not only for me but for my family watching back home. I hope I can build on it."