The Three Lions will begin their campaign with their Group B opener against Russia on Saturday and Smalling is determined to lead a strong defensive performance after Roy Hodgson was criticised for including just three centre-backs in his final 23-man squad.
"I think if anything it just gives you another challenge just to prove people (wrong)," he said.
"There is always doubts, whether it's with England or whether it's with your club form.
"It's just one of those that there is someone else that can come in and do a job better, say me or someone else.
"I think it's just a time to stand up and be counted, and show everyone that you're good enough - more than good enough - to do that job."