The Red Devils opened their 2017-18 Premier League campaign with a 4-0 victory over West Ham United last weekend, and will look to make it six points from an available six when they travel to Swansea City on Saturday afternoon.
Smalling has hinted that the positive atmosphere surrounding the club could see Jose Mourinho's side enjoy a successful campaign.
"It's hard to be able to have 25 players that all get along but I've found in the dressing room everybody is getting on, everyone's joking, we've got music playing and everyone is laughing and joking about," Smalling told The Metro.
"But that's not the case everywhere else. I hear a lot of stories from other clubs and there's a lot more people that don't get on than us so I think we're very blessed to have the changing room that we have.
"[Paul Pogba's] a joker, Jesse [Lingard] is a joker as well. Youngy is up there as well. I think everyone has their mix and no matter what nationality, as we've got so many in that changing room, everybody gets on and has a laugh. I think we're very lucky in that we get to work in an environment that we all really enjoy."
Smalling has been linked with a move away from Man United in this summer's transfer window.