Superman and Clark Kent both have different personalities.

Superman is commonly seen as a brave and kind-hearted hero with a strong sense of justice, morality and righteousness. He adheres to a strict moral code often attributed to the small town American values with which he was raised, thanks to his adoptive parents. His commitment to operating within the law has been an example to many other heroes but has stirred resentment among others, who refer to him as the "big blue boy scout." Superman can be rather rigid in this trait, causing tensions in the superhero community, notably with Wonder Woman (one of his closest friends) after she killed Maxwell Lord.

To protect his secret identity, Superman has constructed a persona in his civilian identity as Clark Kent. To the world at large, Clark is a mild-mannered and clumsy person. Only Lois Lane, his wife, knows that this attitude is just an act.