Arguably Scotland's finest young manager resigned from his post at Alloa Athletic last weekend, having taken the little Clackmannanshire club to two successive promotions. Hartley wants to write a fresh chapter in his career.
When news broke last Saturday night that he had resigned, most were taken by surprise. "What's going on?" people asked. "Something must be up; there must be more to this," it was claimed. Well, Hartley willingly paints a very different picture.
"I've got nothing lined up at all," he says. "People keep asking me this: 'where you going, what you got fixed up?' Honestly, I've got nothing fixed up, I've got no job to go to. It was just time to end the journey I'd been on. It was time for a new journey for me."
But, surely, you don't just walk out on a job, after 2½ highly successful years, to join that growing scrapheap of gifted Scottish managers who cannot get back into the game? "I understand what I've done," Hartley replies. "I've taken myself out of a job and I know it might not be easy getting back in. I look at guys like Craig Levein and others, not working just now. I understand all of that. There are currently 40 guys in for my old Alloa job: 40 guys. So it might not be easy to get back in.
"It is what I think is right for me. I just want to take time out. I want to have a think about what I want to do next. I'm pretty single-minded. I want to see what's out there. I'm very headstrong - when I make a decision, I make it. Hopefully, my cv looks good. I'm a better manager now."
Two very obvious factors helped make up his mind. The first was the way Hartley's devotion to the Alloa job and his ambition to be the best he could be - made clear by his success - became more and more difficult at a part-time club. Then there was the issue of compensation required to be paid when he applied for the recent Inverness Caledonian Thistle job, a factor which probably went against him.
"I felt I needed a new challenge, in terms of working somewhere in a full-time environment, getting to work with players day in, day out," said Hartley. "At Alloa, I only worked with my players for 2½ hours each week, and it's been like that for two years.
"I'd see my players on a Tuesday and a Thursday night, if they made it from work. What people don't realise is that, in part-time football, you can't just turn up with the guys on a Saturday. All the preparation still has to be professional. I was basically full-time in my approach, and in my hours, even though I was actually a part-time manager. I'd do everything, I'd travel for miles in my car each week - to Stranraer or to Elgin - to check on our opponents.
"It just became very difficult. I was treating the job as a full-time job, because I want to succeed, I want to try to be the best manager I can be. I feel I've done a good job at Alloa . . . in fact I think I've done a tremendous job there. When I think back to how it all started there: the club had just been relegated to the third division - the bottom tier - and there were no players. So I had to go and find a whole new squad. It has been a load of hard work these past 2½ years."
Hartley is cautious about saying so, but the turning point in his thinking might have come almost two months ago when, with his cv glittering and his name being tipped for Terry Butcher's job at Inverness, he lost out to John Hughes. It left him pondering how best to advance his career.
"I had two interviews with Caley Thistle," he says. "First, I met their people in Edinburgh - Kenny Cameron [the chairman] and another of their non-execs - where we spoke about what I was about and what I'd hope to bring to the club. I got a second interview, when they asked me to go up to Inverness, and I think I was in the final three.
"That second meeting was on the Sunday and the next day I got a call saying that I had missed the job. I was disappointed for about a day. But then I told myself, 'right, you need to go and try again.' Maybe that Caley Thistle situation gave me a hunger, maybe it spurred me on to try to get to that next level.
"I don't know if not getting it was related to the fact that I was tied to Alloa, and that there would be compensation. Possibly. There would certainly have been compensation involved and, with the lack of money around today, most clubs would rather not pay out money for a new manager, would they? Especially if you wanted to bring your men with you: an assistant, a coach, whatever.
"I said to Kenny Cameron, 'was there something I didn't do right; should I have spoken differently?' But he said, 'no, you interviewed very well . . . the club have just decided to go down another route.' Fair enough."
So, after this first week of freedom in 2½ years, what is he going to do with himself, apart from look for another job? "I'm going to go to some games," says Hartley. "I'm going to go down to England, maybe look at some training methods down there. I'm going to maybe do bits and bobs on radio and TV. I might also do a wee bit of coaching for the SFA."
Hartley certainly has a single-mindedness about him; it becomes very obvious in conversation. Having worked for an array of different managers, it seems suitable to ask, first, whether he is more of a coach or a manager, and, second, which previous manager had shaped him the most?
"I think I'm both [a coach and a manager]. I was very, very hands-on in the job at Alloa. I did about 95% of the training with the players," says Hartley. "I've worked under loads of managers, but at Alloa I never really phoned a manager up looking for advice. I'm just not that type . . . I'm me. This is what you get.
"I worked under Gordon Strachan at Celtic, who was absolutely different class: probably the best manager I've ever worked under. On the training ground he was magnificent. When you were least expecting a bollocking, he gave you one; and when you were expecting it, none came. I loved Gordon, I just thought he was brilliant.
"Craig Levein was another one. He was great at Hearts. He really shaped me into a player. I also played under Walter Smith, who was very good.
"I picked up bits from different managers but, basically, you have to be yourself. That's me, anyway. I go my own course."