Although some of his research involves questions traditionally pursued by linguists, such as the conditions under which a certain linguistic construction is grammatically viable, he is most famous for his ideas about the centrality of metaphor to human thinking, political behavior and society. He is particularly famous for his concept of the "embodied mind" which he has written about in relation to mathematics. In recent years he has applied his work to the realm of politics, and founded a progressive think tank, the Rockridge Institute.

Lakoff began his career as a student and later a teacher of the theory of transformational grammar developed by Massachusetts Institute of Technology professor Noam Chomsky. In the late 1960s, however, he joined with other former students to promote generative semantics as an alternative to Chomsky's generative syntax. In an interview he stated:

"During that period, I was attempting to unify Chomsky's transformational grammar with formal logic. I had helped work out a lot of the early details of Chomsky's theory of grammar. Noam claimed then — and still does, so far as I can tell — that syntax is independent of meaning, context, background knowledge, memory, cognitive processing, communicative intent, and every aspect of the body...In working through the details of his early theory, I found quite a few cases where semantics, context, and other such factors entered into rules governing the syntactic occurrences of phrases and morphemes. I came up with the beginnings of an alternative theory in 1963 and, along with wonderful collaborators like Haj Ross and Jim McCawley, developed it through the sixties." His differences with Chomsky contributed to fierce, acrimonious debates among linguists that have come to be known as the "linguistics wars."

Lakoff's original thesis on conceptual metaphor was expressed in his book with Mark Johnson entitled Metaphors We Live By in 1980.

Metaphor has been seen within the Western scientific tradition as purely a linguistic construction. The essential thrust of Lakoff's work has been the argument that metaphors are primarily a conceptual construction, and indeed are central to the development of thought. He says "Our ordinary conceptual system, in terms of which we both think and act, is fundamentally metaphorical in nature." Non-metaphorical thought is for Lakoff only possible when we talk about purely physical reality. For Lakoff the greater the level of abstraction the more layers of metaphor are required to express it. People do not notice these metaphors for various reasons. One reason is that some metaphors become 'dead' and we no longer recognise their origin. Another reason is that we just don't see what is going on.

For instance, in intellectual debate the underlying metaphor is usually that argument is war:He won the argument , Your claims are indefensible , He shot down all my arguments , His criticisms were right on target  , If you use that strategy, he'll wipe you out .For Lakoff, the development of thought has been the process of developing better metaphors. The application of one domain of knowledge to another domain of knowledge offers new perceptions and understandings.

Lakoff's theory has major consequences if correct. It points to the complete re-evaluation of the entire Western philosophical and scientific traditions. It has applications throughout all academic disciplines and much of human social interaction. Lakoff has explored some of the implications of the embodied mind thesis in a number of books, most written with coauthors.

Scott Adams' book God's Debris is influenced by Lakoff's idea that metaphors are central to the human thought process.

(Further reading: Milton Erickson, the so-called "father of modern hypnotherapy", who was also a strong advocate of metaphor as a means for communication)