John H. Smith

John H. Smith is a common name that could refer to multiple individuals, but generally, it denotes a person with the given name John, middle initial H., and last name Smith. Without additional context, it's difficult to specify who he is. If you are referring to a particular John H. Smith, please provide more details such as his profession, achievements, or the context in which he's known, so I can offer a more accurate and relevant explanation.