Cole has been linked with a move away, but was the matchwinner in West Ham's victory at Ipswich Town.
"Carlton Cole is working very hard," Grant told whufc.com. "His attitude is good. He is a good player. Against Ipswich, he was in the right place at the right time again.
"I think the new system has helped him. We also have a team that know how to play football so they can give him the pass at the right time. If you look at all the goals we have scored this summer, all the goals came from combinations between many players in the team. Of course it is good for him."