In Charles Dickens's Hard Times, Mr. Sleary is a circus owner whose philosophy of life stands in sharp contrast with some of the novel's other characters (especially Thomas Gradgrind, Josiah Bounderby, and Bitzer).

Mr. Sleary is a rather stout fellow with a lisp and a big, kind heart. He takes care of Sissy when her father, a clown with the circus, deserts her, and he encourages Sissy to accept Mr. Gradgrind's offer to live in the Gradgrind household and receive an education. Sissy, however, probably due to Mr. Sleary's early influence, never accepts Mr. Gradgrind's philosophy of life. She has already accepted Mr. Sleary's own philosophy: make the best of life, not the worst.

After Tom robs the bank, Sissy sends him to Mr. Sleary's circus for safety. Mr. Sleary, after pretending to be indignant about the request to help Tom, agrees to take him, noting that Mr. Gradgrind's system of “education” certainly hasn't worked for his son. The clever Mr. Sleary then uses a horse and a dog to distract Bitzer and allow Tom to make his escape.

Mr. Sleary's philosophy is based on love. Society, he believes, is not all about self-interest. People truly must and do care for each other. Further, Mr. Sleary asserts that people must play and have fun. They can't always be focused on education or work. Wisdom and kindness go together, as do learning and amusement.