public class Profile
{
   public string Name { get; set; }
   public string SchoolGrade { get; set; }
}

public class ProfileDTO
{
   public string Name { get; set; }
   public SchoolGradeDTO SchoolGrade { get; set; }
}

public enum SchoolGradeDTO
{
   [Display(Name = "Level One"]
   LevelOne,
   [Display(Name = "Level Two"]
   LevelTwo,
}

Mapper.CreateMap<Profile, ProfileDTO>()
       .ForMember(d => d.SchoolGrade , op => op.MapFrom(o => o.SchoolGrade))

Mapper.CreateMap<Profile, ProfileDTO>()
      .ForMember(d => d.SchoolGrade,
                op => op.ResolveUsing(o=> MapGrade(o.SchoolGrade)));

public static SchoolGradeDTO MapGrade(string grade)
{
    //TODO: function to map a string to a SchoolGradeDTO
}