Remove any loose paint, if the fireplace was previously painted, using a paint scraper.
Scrub the brick surface with soap and water. Allow it to dry thoroughly.
Vacuum away any dust and debris after the brick fireplace is dry.
Place painter's tape over any areas around the fireplace that you want to protect from paint.
Apply a single coat of oil-based primer to the brick fireplace, using a paint roller with a thick nap that's between 3/4 and 1 inch. Make sure you use primer that is suitable for brick and is heat-resistant. Allow it to dry thoroughly.
Apply a heat-resistant, latex paint suitable for masonry surfaces on top of the primer, using a paint roller or a paintbrush.
Allow the first coat of paint to dry, and then apply a second coat. Apply a third coat if necessary.