Kane managed just one goal from his first nine Premier League appearances for Tottenham this season, but has since found the back of the net seven times in his last four outings.
"It was only a matter of time," Walker said.
"He [Kane] is a proven goal-scorer and was always going to continue his form into this year. We all had faith in him but most importantly he had faith in himself.
"When he is playing well, he is unstoppable."