This is far from the type of person, people imagine him to be.
ご質問ありがとうございます。
「これは彼の[イメージ](https://eikaiwa.dmm.com/uknow/questions/42451/)からかけ離れています。」は英語で「This is far from the type of person, people imagine him to be.」と言います。
また、別の言い方で「When people think of him, they would never imagine him being like this.」でも言えます。