ChatGPT will roleplay with you, but it starts every chat as a helpful assistant. If you open with "pretend you're a pirate," you get a pirate who sounds like customer support.
The fix is to give it a full character before the first line of the scene. Here is the setup I use, plus what to do when it slips back into assistant mode.
Start with a character, a style and a scene
A roleplay prompt that works has three parts. The character tells ChatGPT who to be, the writing style tells it how to sound, and the scene tells it where to start.
Here is a template you can paste and fill in:
This is a roleplay. You play [Name], [age], [two or three looks details]. Personality: [two or three traits], [one habit], [what they want]. Background: [one or two sentences of history]. Write in novel style, with description and natural dialogue, and never speak or act for my character. Scene: [time, place, and what is happening]. Start with [Name] reacting to me.
The line about never acting for your character matters more than it looks. Without it, ChatGPT tends to write your replies for you and move the story along on its own.
Keep the setup with Projects or custom instructions
Pasting the same prompt into every new chat gets old fast. A ChatGPT Project lets you save instructions and files that every chat inside it reads, so the character sheet lives there once.
Custom instructions do something similar across all your chats. That is handy for general rules like "write in third person," but a Project keeps each character separate.
Pull it back when it drifts
Long scenes drift. The character gets politer, starts summarizing, or asks what you would like to do next.
A short correction usually works better than restating everything: "Stay in character as [Name]. Shorter reply, more attitude." If the scene is long, paste a three-line recap of what has happened so far and carry on from there.
Where ChatGPT falls short
ChatGPT keeps to OpenAI's content rules, so darker or more mature stories hit a wall sooner than they would on an app built for roleplay. Memory is the other weak spot, since a long story eventually pushes early details out of what the model can see.
If you want ready-made openers, these AI roleplay prompts work in ChatGPT with minor edits. My longer take on why ChatGPT beats Character AI at roleplay has more templates and fixes.
For long campaigns with lore that has to stick, a frontend like SillyTavern gives you lorebooks and lets you pick the model. It takes setup, but your characters and chats stay on your own machine.
What kind of roleplay do you run in ChatGPT? I am curious which genres hold up best.