Born in Chicago in 1926, Putnam graduated in mathematics and philosophy at the University of Pennsylvania (BA, 1948) and then studied at UCLA (PhD, 1951) under Reichenbach's supervision. His academic career led him to Northwestern University and then to Princeton until 1961. Later he was at MIT and then at Harvard until his retirement in 2001. He is married to Ruth Anna Putnam.

For many years regarded as one of the leading analytical philosophers, Putnam had his turning point in the seventies, when he gave up his early "strict" analytical point of view (roughly speaking, a kind of sophisticated physicalism), to embrace a new position called first "internal", then "pragmatic" and, more recently, "naive" or "natural" realism (esplicitly linked to the rediscovery of the tradition of the American Pragmatists, especially William James, John Dewey and Ch.S.Peirce).

Putnam's natural realism is centred on an alleged new account of perception, dismissing the current image of the mind as an organon requiring sense-data as a "cognitive interface" between the world and the conceptual level ("direct realism").

Classified as one of the greatest "neo-pragmatists" (and among the greatest living philosophers), nonetheless Putnam does not agree with the Rortian diagnosis of the contemporary state of philosophy, its dissolution into a sort of disengaged, ironic, literary exercise after the end of "Metaphysics" (especially in relation to the supposed end of the Analytic tradition).

Nevertheless, Putnam's most recent proposal clearly leads to a deflationary approach to ontology and metaphysics (especially with regard to ethical and religious concerns, seemingly influenced by Levinas; finally to philosophy as a whole), a strategy conceived as a necessary step towards the hard task of renewing philosophy.