Kesler was born on August 31, 1984, in Livonia, Michigan, to Linda and Mike Kesler. He is the youngest of three children, after brother Todd and sister Jenny. His father, Mike, played college hockey at Colorado College and was a supervisor with the Blue Cross and Blue Shield Association for 37 years. He introduced his children to the ice at a very young age; Ryan recalls skating at around age four. Mike also coaches a Junior B hockey team and runs a hockey school in Livonia, which Kesler attended as a child every summer from the age of six to seventeen. In April 2007, Mike was diagnosed with carcinoid cancer and had seven inches of his small intestine removed in order to be rid of it.