After the war, Cooke resumed his fiction writing, often focused on detailing the Southern experience. Before the war, many of his writings were set in colonial times; after the war, they were almost exclusively set in war time. Perhaps more importantly, he had been somewhat liberal and reform-minded before the war. After, he conformed to certain standards for Southern writers in the hopes of achieving significant commercial success. As he admitted, his intention was "to become the writer of the South yet!" To that end, his version of the Southern experience was bucolic, full of myth, and sometimes antagonistic to the north.
By the end of his life, he had published more than 30 books. Among those books are historical romances, biography (including one of Robert E. Lee and another of "Stonewall" Jackson, and collections of short stories. In more recent years, an organization has named a fiction prize in Cooke's honor; it is granted to books on the Civil War or Southern heritage. From Cooke's 1867 novel Wearing the Gray:
Of all human faculties, surely the most curious is the memory. Capricious, whimsical, illogical, acting ever in accordance with its own wild will, it loses so many "important events" to retain the veriest trifles in its deathless clutch. Ask a soldier who has fought all day long in some world-losing battle, what he remembers most vividly, and he will tell you that he has well-nigh forgotten the most desperate charges, but recalls with perfect distinctness the joy he experienced in swallowing a mouthful of water from the canteen on the body of a dead enemy.