See, for example: A Rare Blend of Monster Raving Egomania and Utter Batshit Insanity (2002) http://bactra.org/reviews/wolfram/

I met Wolfram some 20 years before that review when he was on a world tour promoting the earliest iterations of Mathematica, the first iteration post his symbolic differentation work.

This was the period when cellular automata, Mandelbrot sets, and symbolic math were pretty hot topics about math departments - computer assisted proofs on monster groups in symbolic algebra were recent, Cayley (the first iteration of Magma) was being written at Sydney University, etc.

Even then he had many of the traits that Cosma Shalizi described in the linked review above and was already dismissing various people for their 'poor ideas' and later claiming those ideas as his own.

He's a smart guy. He swam in waters filled with smart people, some smarter. He was never, IMHO, as smart as his own legend, as authored by himself.