When do you use a comma before and after a name in a sentence?

When addressing a person directly, always use commas:

"See, John, I told you that we'd get along."

When clarifying a unique person's name:

"My grandmother, Mary, will meet us at the restaurant."

Following their title, or before a more formal title:

"Chief Physician, John Mark, M.D., argued that the resources were inefficient."