Campo is not surprised that his former boss has made a successful start to life in east London.
"For me, Sam is a very special coach because he has very clear ideas about football and he always wants what's best for his players," Campo told the official West Ham match programme.
"Motivating players is very important and Sam knew how to motivate everyone for every game to how to produce good performances from us. At key points during the season it's crucial to get big performances from your players and Sam could do that.
"He's a lovely, lovely man. He is a very good friend and an absolutely fantastic coach. It's very important in football to be honest about performances, selection and tactics and Sam is a very honest man.
"When I was playing at Bolton with Sam as our coach we celebrated many good times with the players, fans and the club and a lot of that success was down to Sam."