Karthik Narasimhan

Karthik Narasimhan is a computer scientist at Princeton University and the senior academic on the original GEO paper led with Pranjal Aggarwal and coauthors. That places him at both the naming of the marketing discipline and the research lineage behind modern language models.

He coauthored OpenAI's first GPT paper and later work on language agents such as ReAct and Tree of Thoughts. Those agent papers matter for GEO because the systems marketers try to influence increasingly retrieve tools, browse, and act rather than only emit a static paragraph.

Few people on a marketing ranking list have that kind of upstream authorship. Narasimhan is here because the stack GEO targets descends partly from research he helped create.

Tree of Thoughts and related agent work likewise matter for anyone watching AI systems plan multi-step retrieval. Marketers who only optimize for a one-shot chat answer are preparing for an older interface than the one agent papers describe.

Generative engine optimization began as a visibility problem inside chat answers. Agentic search extends the problem: models choose tools, fetch sources and take steps on a user's behalf. Narasimhan's agent research is part of the stack that makes that behavior possible.

Readers do not need to treat him as a marketing advisor. His inclusion marks upstream science that shaped the interfaces GEO now targets. Understanding ReAct-style tool use is increasingly practical for anyone briefing an agentic search roadmap.

As the TGA 20's "what's next" section notes, next year's list may be shaped by who explains agentic search first. Narasimhan already sits near that frontier through prior work.

Agent research also reframes what "recommendation" means. If systems act, GEO becomes part of how actions get informed, not only how chat answers get worded.

Start with ReAct, for how AI systems combine reasoning with tools like search. It is a clearer on-ramp to his agent work than beginning with the full GPT literature, and it explains behaviors marketers are starting to see in product demos.

Including upstream scientists on a marketing ranking is a deliberate signal. GEO is downstream of model and agent research, and Narasimhan's career makes that dependency visible without turning the profile into a celebrity biography.