If you take a look in the 5E Dungeon Master Guide, you will see Chapter 4: Creating Non-Player Characters. It mentions these specific aspects of a memorable NPC character:

Occupation and history
Appearance
Abilities
Talent
Mannerism
Interactions with others
Useful knowledge
Ideals
Bonds/allegiance
Flaws or secrets

They even give tables so you could create a detailed NPC in just a few die rolls. Gosh, if you have writer's block, this is the place to go! Occupation is certainly on the list, but it is just one of many things, and there is very little discussion of occupation in Chapter 4 except for the villainous variants given at the end. Chapter 4 shows you how an AI algorithm might be able to create the NPC's, possibly with input from the player. In fact, Argyle might already be an AI thing ... how would you know?