Longus is known only as the author of the Greek novel Daphnis and Chloe. Stylistic analysis places him in the late 2nd or early 3rd century CE, within the cultural context of the Second Sophistic. The pastoral setting on Lesbos suggests possible familiarity with the region, though this remains speculative.

His sole surviving work is the prose novel Daphnis and Chloe, written in four books in an Atticizing dialect. Longus authored one of the five complete ancient Greek novels. Daphnis and Chloe is distinctive for its pastoral idealization and focus on innocent, natural love. A key example of Second Sophistic prose revival, its depiction of erotic development and rural life profoundly influenced later European literature, opera, and ballet.