Gfilui

Any craftsman during their journeyman years.

A journeyman is a craftsman who just completed their apprenticeship. There was a custom during the middle ages (especially in the German-speaking area) called the "Walz". Young craftspeople spent three years and one day with traveling to other cities, seeking contact to the locals of the same profession and exchange knowledge and experience in the craft. The purpose was to spread crafting know-how geographically.

Some professions practice this tradition to this day.

Using a journeyman as your main character has several great storytelling opportunities:

• They go to unfamiliar locations with the goal to learn about the local customs. That gives you plenty of opportunities to weave infodumps into conversations and observations without breaking immersion.


• They have a reason to interact with many different people. Seeking contact to their peers is literally their motivation. But they also have opportunities to interact with lower-class people (if just to ask for directions) as well as higher-class people (to ask for work). As inexperienced outsiders they might also be of interest to more shady characters, both as victims and as pawns.


• They are young adults, so they have plenty of room for character development.

• 
  Artist and technical people: musicians, painters, sculptors, architects, engineers, craftsman. They had to go where somebody willing to pay for their work was present (see Leonardo da Vinci)


• 
  Soldier: if you are smart you don't fight wars in your backyard, therefore you travel and hope to come back


• 
  Pilgrim: not strictly a profession, but still taking long time


• 
  Cleric: again, one had to go where the Order sent him


• 
  Tax man or bureaucrat: go where the government send you


• 
  Sex worker: chase the customers and escape the moralists

Here are a few more professions which might travel during the middle ages...

• Clergy


• Messengers


• Royal Inspectors


• Day Laborers


• Spies posing as any of the above


• Criminals posing as Day Laborers

Coachmen. Because most people described in other answers will need a ride.

From the Assassin's Creed II Animus database:

Travel in the Renaissance was not the disgusting ordeal it is today. Instead, it was merely terrifying. The countryside was filled with bandits, causing most travellers to move in armed groups called caravans. Anxious voyagers usually sewed valuables and gold into the soles of their shoes or the lining of their jackets.

Guides called Vetturini were sometimes hired to help plot the route of the caravans and book rooms at local inns, but those carriers were often working with the bandits, just like travel agents today.

People associated with the judiciary. Most prominently judges, but of course also their retinue (judges were important people, so they would have servants, grooms etc.) and lawyers.

In the Middle Ages, lawsuits, whether civil or criminal would be handled by different tribunals. Lesser affairs would be handled by local magistrates, but more important cases would wait for the court to come around. This is where the term "circuit court" originated, which is still in use in common law systems like the US:

King Henry II instituted the custom of having judges ride the circuit each year to hear cases, rather than requiring every citizen to bring their cases to London (see Assize of Clarendon).[2] Thus, the term "circuit court" is derived from the practice of having judges ride around the countryside each year on pre-set paths − circuits − to hear cases.

I am almost certain that the same practice prevailed in France and Germany, but can't find a source right now. Especially in the more centralized (and centralizing) kingdoms, this practice played an important role in standardizing the application of law beyond the immediate environs of the lawgiver.

Previous answers have been quite exhaustive, so I'm going to add an esoteric example into the fray!

How about a 'Coney-Catcher?

Sourced from Wikipedia:

Coney-catching is Elizabethan slang for theft through trickery. It comes from the word "coney" (sometimes spelled conny), meaning a rabbit raised for the table and thus tame.

A coney-catcher was a thief or con man.

[...]

The term was first used in print by Robert Greene in a series of 1592 pamphlets, the titles of which included "The Defence of Conny-catching," in which he argued there were worse crimes to be found among "reputable" people, and "A Disputation betweene a Hee Conny-catcher and a Shee Conny-catcher."

Since the term originates in medieval England, your 'rogue' character can equivocate or reject the term 'Coney-Catcher' if you wish as it is a new term at that time.

Alternatively, you might embrace that word and its meaning entirely. It is around this time the idiom of buying 'a pig in a poke' materialises; selling a dead cat in a sack and claiming it is a pig is a classic 'Coney-Catcher' con.

Greene gives other examples in his pamphlets, providing you with plenty of historically accurate (albeit sensationalised) material to develop.

Ronin.

https://www.deviantart.com/maxromanchak/art/Lone-Wolf-And-Cub-284013200

Medieval Europe is pretty well covered in previous answers. For a few more ideas consult Canterbury Tales which features characters from less well known medieval professions like Summoner and Pardoner.

Ronin is from medieval Japan.

https://en.wikipedia.org/wiki/R%C5%8Dnin
A rōnin (浪人, "drifter" or "wanderer") was a samurai without a lord or master during the feudal period (1185–1868) of Japan. A samurai became masterless from the death or fall of his master, or after the loss of his master's favor or privilege.

Ronin are well suited for protagonists - formidable, desperate, adrift and honorless.

Depicted: Lone Wolf and Cub, from a sweet series featuring a ronin samurai and his son.

One more: minstrel, entertainer. Sorry if I missed someone else saying it.
And a maybe: I wouldn’t call myself an adventurer, but I retired, sold my house, and have been roaming since.

Some additional professions, that came to my mind:

• Mercenary


• Assassin or hitman


• nomadic cultural entertainer (Showmen maybe like the Edema Ruh in the Kingkiller Chronicles)


• Tinker


• Taxman (if you want your character to be unpopular)


• a bit unusual at that time but maybe interesting: historian, archaeologist like Ciriaco de' Pizzicolli or cartographer

Remember, that you can combine several professions.

One missing profession is academic. There were universities in the medieval period- several teaching philosophy, latin and theology and the professors and students would transfer around.

How about ambassador? In medieval times there weren't full time ambassadors but rulers did have to select people to send on embassies to other rulers. Thus someone whose normal life style might have been stay at home or wanderer would be sent with a small group on a journey of sometimes hundreds or thousands of miles.

And there was missionary. A person would go or be sent as a missionary to some foreign land and become revered as someone who revealed the truth to the people, or instantly martyred for trying to replace the old religion, or be treated somewhere in between, and he might settle down in one spot in the land he was sent to, or else travel hundreds or thousands of miles a year on missionary business.

And there was slave. A slave might be enslaved by some method in one country and be transported hundreds or thousands of miles to another country to be sold. Many Muslim countries used foreign slaves as soldiers, so a slave could find himself invading a third country in the service of the ruler who owned him. Slave soldiers often became free and sometimes became lords and even sometimes rulers of a whole country.

Monks had a number of reasons that they might travel regularly and potentially for extended periods.

From The Time Traveler's Guide to Medieval England by Ian Mortimer:

...If monks have withdrawn from the world to live lives of contemplation and prayer, how come you meet so many of them outside their cloisters, journeying around the country? The answer is monastic business. Abbots and priors need to attend meetings of their Order, and many abbots and a couple of priors are summoned to attend Parliament. Some traveling is undertaken by other monks to acquire things-including manuscripts to copy for the monastic-library-or to exchange news. But the vast bulk of monastic business is to oversee the abbey's estates. The monk in Chaucer's "Sea Captain's Tale" is allowed by his abbot to roam where he wants on the pretext of inspecting the monastic granges. Some monasteries have a great number of these, with vast estates all over the south of England.

Couriers travelled between ruling municipalities to carry messages to both rulers and common-folk. Signed, Sealed, Delivered: How Messages were sent in the Middle Ages

A courier could be anyone from a serf to clergy to soldier to nobility. This gives a wide range of options for character assignment.

These couriers would also be good candidates for intelligence gathering.

There were the pot mender, scissor and knife sharpeners and pot tinner who would make rounds. These were often called Tinkers they would also have all sorts of arcane skills and tools that an unlikely hero could make use of.

Another class who moved were the servants of all of the others who had due cause the move.

Seasonal workers would follow the crops and pick, harvest or thresh the produce as it became ripe. In sheep country you would have travelling sheep shearers.

Obviously the witch burners and other institutionalised religious people would try to get all over.