Utterson is Jekyll's loyal friend and it is through his perspective that we understand most of the novel. His loyalty to, and concern for, Jekyll are shown often.

When Sir Danvers Carew is murdered, Utterson protects his friend Jekyll by not mentioning their relationship to the police. Utterson is a lawyer and therefore a respectable, wealthy man in Victorian London.

He is calm and rational and rather like a scientist in his approach to life. He likes to weigh up the evidence. He is also curious and persistent which we see in his quest to uncover the true reality and motives of Mr Hyde.

If he shall be Mr Hyde, he had thought, I shall be Mr Seek.Dr. Jekyll and Mr. Hyde, Robert Louis Stevenson

It is this curiosity and persistence that eventually sees him uncover the truth about Dr Jekyll and Mr Hyde's relationship.

"lean, long, dusty, dreary and yet somehow lovable"Utterson is a serious-minded man with a respectable and serious profession. He is still "lovable" though.
"He had an approved tolerance for others..."This shows Utterson to be a tolerant person willing to consider and appreciate views and ideas that he considers wrong.
"the last reputable acquaintance and the last good influence in the lives of down going men"Utterson, by reputation is a loyal friend willing to help those around him.