In 1942, he interrupted his studies to serve in the U.S. Army Air Corps as a meteorologist, having been turned down for cryptology work because of his "enemy alien" status.

He published a short paper in Datamation in 1962 entitled "How to Make a Computer Appear Intelligent" that described the strategy used in a Gomoku program that could beat novice players.

[4] In 1966, he published a comparatively simple program called ELIZA, named after the ingénue in George Bernard Shaw's Pygmalion, which could chat to the user.

Driven by a script named DOCTOR, it was capable of engaging humans in a conversation which bore a striking resemblance to one with an empathic psychologist.

Weizenbaum modeled its conversational style after Carl Rogers, who introduced the use of open-ended questions to encourage patients to communicate more effectively with therapists.

His belief was that the computer, at its most base level, is a fundamentally conservative force and that despite being a technological innovation, it would end up hindering social progress.

When asked about his belief that a computer science professional would more often than not end up working with defense, Weizenbaum detailed his position on the effect of rhetoric, specifically euphemism, on public viewpoints.

He made it clear that he did not think of himself as a pacifist, believing that there are certainly times where arms are necessary, but by referring to defense as killings and bombings, humanity as a whole would be less inclined to embrace violent reactions so quickly.

Instead, Weizenbaum asserts that the definition of tasks and the selection of criteria for their completion is a creative act that relies on human values, which cannot come from computers.