Chafin was a 23rd century Human male. By the 2250s, Chafin was serving as a crewperson in Starfleet, assigned as a security officer aboard the USS Constitution. In 2257, Chafin and his colleague, Reboulet, was assigned to accompany Lieutenant Jack Gaynor and a landing party to the N'shaii mothership in order to guard Lieutenants' Borrik and Polcovich as they worked on disabling the ship's link to their satellites. Chafin succeeded in stunning one of the N'shaii with his phaser in an attempt to prevent him warning the rest of the ship's crew. A few minutes later, Chafin came under attack by N'shaii reinforcements and suffered severe damage to his right shoulder. Chafin later returned to the Constitution where he received medical attention for his injuries.