The Lost Fleet Series by Jack Campbell

The Lost Fleet series is set one-hundred-plus years into an interstellar war between two different human cultures, the Alliance and the Syndics. The protagonist of the story is discovered floating in a suspended animation escape pod one-hundred years after he made a "heroic last stand" against an enemy fleet. In the present, he's a renowned hero to the Alliance and his name and actions are used to justify poor tactics and decisions. Awakened after being discovered during a secret mission that turns out to be an enemy trap, he's suddenly dropped into the fleet commander's chair and expected to live up to the legend that has grown around him.