" Just because Don gets emotional, he thought this was the case with Charlie and even stated his brother was backing one of his own.
In "Trust Metric", Charlie says that he has a giant ego.
He taught at the FBI Academy for a time after Fugitive Recovery to help him come back to civilization ("Longshot").
After that, he worked in the field office in Albuquerque, New Mexico, and dated Kim Hall (Sarah Wayne Callies), and nearly married her.
Don graduated high school on the same day as his younger brother Charlie, who is five years younger ("Soft Target").
He went to college on a baseball scholarship and then played Single-A with the Stockton Rangers (a fictional team) as a utility player.
Sometimes, he feels that Charlie isn't doing all the great things he could be doing because he is working with the FBI.According to actor Rob Morrow, Don has a tendency to sacrifice, even at the expense of what he wants from life.