In short and simple terms, the phrase "good head" typically refers to someone who is skilled, knowledgeable, or competent in a particular area or field.
After all, everyone knows that horse lovers are great people with good heads on their shoulders! (equestrianchatcity.com)
Now obviously it says right on the package what was in them so I got a pretty good head start on them, but gave them some creativity and flair of my own! (tornadoughalli.com)
Looking to meet single, well rounded men with good heads on their shoulders. (doctordatingservice.com)