A great man is someone who is a highly influential individuals, either from personal charisma, genius intellects, or great political impact. (from
Wikipedia)
However, whether that person is a so called "good person" is opened to debate... because what can be termed "good" by one person could called "evil" by another...
If you take Adolph Hitler as the quintessential example... though reviled by most... he could not have attained his status without the staunch support of admirers and followers...
.