The Senegal international has been in impressive form for the Hammers and has scored five goals in his last five games.
However, he has revealed that a move to the club almost fell through before co-owner David Sullivan intervened.
"I have always wanted to play in England and when West Ham came in for me in the summer, I thought that was it," The Mirror quotes him as saying.
"But then the deal began to fall through as I think the coach was having doubts and I was resigned to returning to France.
"Fortunately for me, Mr Sullivan stepped in and said he would be signing me and on a permanent deal. It was the chance I needed."
Sakho scored for West Ham during their 2-0 win over Queens Park Rangers on Sunday.