I spent some time thinking about what Harry did after the war with Voldemort. This was the result.
Disclaimer: I don't own the Harry Potter books
Harry spent most of his time the Auror department sitting down. He didn't actually mind this. Many others thought he should but Harry actually enjoyed it.
He had been drafted/recruited to the Aurors in the aftermath of the battle of Hogwarts when there had still been many Death Eaters on the run that needed catching. Ron, Hermione, and him had all joined with the Aurors and the Order of Phoenix to provide necessary manpower to the depleted ranks so the Death Eaters could be caught before they regrouped and picked a new leader. As summer passed plans were made to reopen Hogwarts for the next school year. Hermione left to retake her final year but Harry and Ron decided not to. (Harry had never had the opportunity to ask if Ron declined, not so he would never have to do homework again, but for the same reason as Harry. Because the building that had once been home was now filled with memories of death and destruction and it was too soon to try confronting them completely.) So Harry and Ron stayed with Aurors and it was assumed that they would be staying for the long haul. They were set up with proper badges and desks and suddenly they were officially Aurors.
Ron left after a year. Harry couldn't blame him. Going after dark wizards again and again with little respite was stressful especially after the war and so many deaths. Besides, George needed help running Weasley's Wizard's Wheezes. He was starting to recover from Fred's death but it was hard. (It was hard for everyone. How could two become one?) Ron had been Harry's partner so when he left Harry was assign a few other partners. He tried doing a couple of solo missions at first but his supervisor said he was being too "risky." None of his new partners worked with him as well as Ron had. There would be miscommunications in the field nearly ending in disaster. When Harry's supervisor had hesitantly pulled him to the side and suggested he be taken off field work he wasn't sure what to think.
On one hand Harry was happy for the break from action. It wasn't like he was doing well with his current partner anyway. (She kept staring at him as though she couldn't believe he was real. Not focusing on the things she should be.) In some ways it felt like he had been going nonstop since Voldemort had returned during his fourth year. He could pause and breath. Let someone else worry about the dark wizards for a while.
On the other hand, this meant stopping and thinking and letting someone else worry about the dark wizards for a while. He couldn't help but feel like he could do more if he was out there physically chasing down those who would hurt others. Paperwork was one of the most boring things in existence. Surely someone else could do this while he was in the field doing something productive? The fact that part of the reason he was put on desk duty was because the higher ups didn't want to risk anything happening to the "Boy Who Lived" was further reason to dislike his new posting. After a few months he asked to be moved back to field work and was denied.
"What you need is another outlet for your savior complex," Hermione told him when he met her after being told he was staying on desk work. "It will make the whole thing more bearable for you."
"Like what? The whole point is I've been benched from helping save people."
"Not exactly. You can't rush in and rescue people from big bad dark wizards anymore, at least not without making superiors angry, but you can help indirectly. Help raise awareness for important issues, raise money for good causes. Use that celebrity status of yours."
So Harry found himself using his "Boy Who Lived" popularity to try and drum up support for the various reforms Hermione was trying to push through the many layers of bureaucracy that made up the government. He was helping people, he supposed. These reforms were for the benefit of everyone but he hated it. Having to go to parties just so people could fawn over the "Boy Who Lived" and do nothing else was boring and humiliating. After a while he just asked Hermione to stop inviting him.
The paperwork was still boring, not to mention frustrating. He considered quitting but couldn't think of anything he would do instead. However, the thought of having nothing to do was worse than just having something incredibly boring to do. So he stayed. He was mainly reviewing case files from recently completed cases. (It served as a constant reminder of what he could be doing instead of sitting at a desk. It was terrible.) he reviewed the reports, checked them for grammar and spelling (why they thought he was qualified for that was a mystery), and got them properly filed. There was one thing he couldn't help but notice in the reports. Aurors were required to report all their mistakes in the field so they could learn from their mistakes. The mistakes section was always filled. It was to be expected, there was always something unaccounted for in the field or a plan gone awry but these mistakes were the sort that could easily be fixed. An improper reaction to some doxies, a shield charm that didn't work as well as it should have, lack of knowledge on how to react to a nonaggressive werewolf. The list went on. It occurred to Harry that many of these things could, and should, be taught as part of basic Defense Against the Dark Arts.
The final straw was the Dementors. After the Ministry quit using them at Azkaban no one knew what to do with them. They were rounded up by some dark creature specialists and taken to an isolated island but inevitably some escaped. It fell to the Aurors to try and round up the escapees and return them. This was more than slightly hampered by the fact that only a few Aurors knew how to properly cast a Patronus charm.
"It's ridiculous!" Harry declared during a date with Ginny. He probably shouldn't have been ranting about work during a date but he was too worked up to care about proper etiquette. "I know it's supposed to be an advanced charm but I was able to teach it to nearly all the DA in fifth year. More people should know it than that."
"I think it's just because you're such a good teacher," she said. "If those Aurors had someone to teach them how to do it properly they could probably do it as well."
The comment stuck in his mind and soon enough Harry found himself suggesting that he teach training session on how to properly cast a Patronus charm. This actually came as a relief to the heads of the department. Aurors never used to need to know the Patronus charm, though the knowledge was considered useful, so it had never gone in the training program. Most of the more experienced Aurors who had known it had either died during the war or retired shortly after.
Harry was taken off paperwork duty and put in charge of special training sessions. He found that he still enjoyed teaching just as much as he had back in school. His new job also meant he was helping people. He was teaching the other Aurors skills that could, and would, save lives in the field.
But soon enough the initial round of training sessions ended and he was put back on paperwork duty. Harry found himself skimming the reports for anything else that could possibly require extra training sessions. He found a few other issues that weren't covered by the Auror training that was supposed to come at the beginning of a career but those only got him away from paperwork for so long.
A few months later he asked for transfer.
"I'm not putting you back on field duty," his supervisor growled.
"I'm not asking to be put on field duty," Harry replied.
"Well then what do you want?"
"I want to help train the new Aurors."
"…You realize that's a job we usually just give the guys on the brick of retirement, right?"
"Well, it will be better than doing paperwork all day. Besides, who better to train them than the man who defeated Voldemort."
The request was processed quickly and soon Harry Potter was in charge of combat training for new Aurors. It involved a bit more sitting down than expected as he sat in the corner and watched the practice duels to see where improvement was needed but it was still nice.
It wasn't where he thought about when he told Professor McGonagall he wanted to become an Auror back at Hogwarts. He did spend a good deal of time sitting down. But he enjoyed it. Every so often someone would ask him if he wouldn't like to get back in the field since, "surely that would be better for a man of your abilities?"
"I'm like what I'm doing now just fine." He told them. And it was true.