A cobalt-catalyzed C–H activation and isocyanide insertion of tryptamine derivatives has been developed for the construction of indole-2-carboxamide scaffolds. By using Co(OAc)2·4H2O as the non-noble catalyst, the reaction worked well to give various indole-2-carboxamides in moderate to high yields. Furthermore, the mechanistic experiments indicated that the Co(III) species was the active catalyst in a non-radical reaction pathway. Notably, silver salt as the oxidant could be recycled and reused.