How do I keep messaging consistent across several creators in one campaign?

You keep messaging consistent by giving every creator the same core message and non-negotiables while letting each express it in their own voice, which is consistency of substance not of script.

Write one brief that fixes the key message, must-say points, disclosures and boundaries for everyone, then leave the wording and format to each creator.

Fix the what and free the how, since a campaign is coherent when every creator carries the same message in a voice their own audience believes.

The key is to define consistency as sameness of message, not sameness of words, because those are very different goals and only one of them helps. You achieve it by writing a single clear brief that fixes the things that must be constant across every creator: the core message the campaign is communicating, the specific must-say points, any required claims or disclosures and the boundaries of what not to say. Every creator gets that same brief, so the campaign speaks with one voice on substance, the same key idea reaches every audience, the same essential points get made and nothing important is dropped or contradicted. That shared core is what makes a multi-creator campaign read as one coherent thing rather than a dozen disconnected posts.

The other half and the part brands get wrong, is deliberately leaving the expression to each creator. Once the core message and non-negotiables are set, the wording, format, framing and style should be left to the creator, because the entire value of using multiple creators is reaching different communities each in a voice they trust and handing every creator an identical script produces cloned, robotic content that their audiences recognise as a copy-paste ad and tune out, which destroys the reach you paid for. So consistency is about every creator carrying the same message, not every creator using the same sentences. The two failure modes mark the edges: too vague a brief and the message drifts, creators emphasise different things and the campaign loses coherence, while too rigid a script and you kill the authentic voices that made the creators worth using. The sweet spot is a firm shared core with free individual execution. So you ensure consistent messaging by fixing the key message and non-negotiables in one brief for everyone and freeing the wording to each creator, since a campaign is coherent when every creator carries the same message in a voice their own audience believes.

Consistent messaging lands more easily when every creator genuinely fits the campaign, which is where influencer discovery helps, assembling a set of well-matched creators whose styles and audiences suit one coherent message. A coherent roster carries a shared message naturally, while a mismatched one fights it. Choose creators who fit the campaign, give them one clear core brief and free the wording, so the message stays consistent across voices their audiences trust.