The Northampton hooker has just served an eight-week suspension for biting the finger of Ireland flanker Stephen Ferris in the last game of England's RBS 6 Nations campaign.
Hartley had pleaded not guilty but the disciplinary panel ruled his reaction to Ferris' finger being inadvertently in or near his mouth was "not justifiable".
England forwards coach Graham Rowntree was among those who helped limit the sanction by arguing Hartley was a changed man from the young hot-head who served a six-month ban for gouging in 2007.
But Hartley was still hit with a suspension, which expired on Monday, and fresh damage to a reputation he had worked so hard to correct.
"That is the most damning thing for me. I had got to the stage where I had finally started proving people wrong," said Hartley, who was limited in what he could say on the verdict.
"I have had to deal with the gouging label. I was on the right path. It is easy for someone reading this to think 'he is a biter' but I have had players come to me who understand the circumstances.
"I had to accept the ban. I won't go into details about how I feel about it. I can't really talk about it. As long as the right people know (what happened)."
England coach Stuart Lancaster has stamped down on ill-discipline during his reign but the national team management were all behind Hartley.
Hartley has been reminded about the importance of on-field discipline but there was never any question he would be omitted from the summer tour to South Africa.
The Springboks will know what happened and they are sure to test Hartley's composure. What if he finds fingers in or near his mouth again?
"I am definitely able to cope if I am provoked," Hartley said.
"South Africans might see this as a weakness and they could come for me there but I know that and I will be prepared for it and I know how to deal with it."
Hartley will face a former Springbok captain tomorrow in Barbarians hooker John Smit but he does not expect any issues from the Saracens hooker.
"He is a good bloke and a good player. He doesn't need to be anything else," Hartley said.
"I have had one eye on this date for a very long time. Whether it was the Premiership final (with Northampton) or the Barbarians game, I knew I was going to be playing this weekend.
"It gave me something to focus on and deal with the obvious disappointment of not being able to contribute on the field for Northampton.
"I have had two months getting myself in the mood. I have been looking forward to this.
"As a team it is a good chance to set ourselves up for the tour. Get a good win under our belt and get some confidence because this Barbarians team is impressive on paper."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The Barbarians are one of the top invitational rugby sides with a long history and classic rugby jersey.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Lions get ready for their matches with this green training jersey. It's what the players wear. Get in the Gear!
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The Lions are ready to get their Australia tour underway. They arrive in Perth on Monday.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.