In other words, would I need to do some string processing after invoking the Application.GetOpenFileName() Method?
In this case, you are using Application.GetOpenFilename(), so you are sure that file physically exists on disk, so the simplest approach will be to use Dir().
fileName = Dir(filePath)
Full code is:
Dim fileName, filePath As Variant
filePath = Application.GetOpenFilename("Excel files (*.xlsm), *.xlsm", , "Select desired file", , False)
If filePath = False Then
MsgBox "No file selected.", vbExclamation, "Sorry!"
Exit Sub
Else
'Remove path from full filename
fileName = Dir(filePath)
'Print file name (with extension)
MsgBox "File selected." & vbCr & vbCr & fileName, vbInformation, "Sucess!"
End If