Pulis told BBC Radio Stoke: "Jon's come from the Championship and sometimes it takes time to have the confidence and the belief to make the step up.
"He had an up-and-down start but he's been fantastic for us."
Walters joined Stoke from Ipswich for an initial fee of ?2.75m in August and has scored nine goals for the Potters this season.
"He's certainly my type of player," added Pulis. "He gives everything, he never stops and whatever you've paid him, you know he's earned it."
Midfielder Glenn Whelan heaped more praise on his Republic of Ireland team-mate: "He's been a class signing for us.
"In the last two months he's come on leaps and bounds and he's given defenders an awful time.
"He's done that against two defenders [John Terry and David Luiz] who are probably in the best three in the world."
Didier Drogba equalised for Chelsea after Walters' early opener at the Britannia Stadium.
It was the first time that Stoke had picked up a point against Chelsea in six Premier League meetings between the two teams.
Source: BBC Sport
Source: BBC Sport