A self-supporting post leveling device (10) operable to both level and support a post (12) or other structural or support member, such as, for example, a pole or beam, during erection or installation. The device (10) broadly comprises an adjustable sleeve (14), including two post adjustment mechanisms (16,18); two leveling mechanisms (20,22); and two, three, four or more legs (24,26,28,30). The post (12) is received within and substantially surrounded by the sleeve (14). The post adjustment mechanisms (16,18) tighten to immobilize the post (12) within the sleeve (14). The leveling mechanisms (20,22), such as, for example, fluid bubble leveling mechanisms or laser leveling mechanisms, may be secured to or incorporated within the sleeve (14). The legs (24,26,28,30) support the sleeve (14) and the post (12) immobilized therewithin.