Before painting a brick fireplace, sand the bricks with 120-grit sandpaper to remove loose particles. Clean the bricks thoroughly using a wire scrub brush, nonsudsy trisodium phosphate and a heavy duty cleaner. Once the bricks dry completely, tape off the area and apply a primer to help prevent soot stains.
Indoor latex paint works well on the exterior of a brick fireplace, provided that it has the ability to withstand the fire's heat. The interior of a brick fireplace requires a special kind of paint. Use a roller designed for textured surfaces and apply two to three coats of paint. Use a paintbrush to fill in any areas you miss.