The Benin international arrived at The Hawthorns on transfer deadline day in what eventually turned out to be an acrimonious departure from Wearside.
Sessegnon had a lot of fans at the Stadium of Light but divided opinion due to his enigmatic demeanour, with Black Cats boss Paolo Di Canio questioning his commitment after selling him to Albion.
Baggies boss Clarke has yet to get to know the forward but has no doubt the player will be raring to go should he make his bow on Saturday.
"I won't have to motivate Stephane," he said.
"He's just joined a new club and he's got a new challenge. You can see every day in training that he's excited about the prospect of playing here and he's looking forward to the game at the weekend.
"I don't think it would matter who we were playing, he'd still be looking forward to it.
"I haven't read Paolo's comments because I tend not to read the media. I'm not really sure what the context was.
"Sometimes when a player leaves a club the manager will choose to make some critical comments but that's for every individual to decide how they want to do it.
"I've only known Stephane for 10 days or so. It's not very long and I haven't had too many chats with him.
"He's quiet, but when I was young I was quiet as well. That doesn't make you introverted or a difficult character. Some people are quiet, some people are loud.
"Everybody has their own character."
Asked if this weekend would be the ideal time to make his debut, Clarke smiled wryly and only said: "You'd think it would be a perfect game, yes."
Sessegnon was unable to pull on an Albion shirt for the first time against Fulham last week due to a glitch with his work permit. However, that was sorted out this week to enable him to play.
"I was disappointed not to have Stephane last weekend and obviously he himself was disappointed that he had to have another weekend off," said Clarke.
"But the work permit has come through and he's in the squad for this weekend.
"I'm not sure what the delay was, to be honest. We thought we'd get it last Friday afternoon but it didn't come through and then it dragged over the weekend but I'm not sure what the delay was - some kind of legal jargon or whatever. It's not my department."
Clarke will come up against Di Canio for the first time as managers on Saturday and is looking forward to it.
"I don't really know him at all, to be honest," he said.
"I must have played against him at some stage but I don't know much about him. I look forward to meeting him at the weekend though because he seems a bit of a character."
He added: "I think all football managers and coaches are passionate but everybody shows it in a different way.
"Obviously Paolo's way is different to my way but that doesn't mean I'm any less passionate about the game."