After the war, Feynman joined the faculty of Cornell University as a professor of theoretical physics. He quickly established himself as a brilliant and innovative teacher, attracting talented students and inspiring them with his unconventional teaching style.

In 1950, Feynman moved to the California Institute of Technology (Caltech), where he remained for the rest of his career. At Caltech, he continued his groundbreaking research in quantum electrodynamics (QED) and other areas of physics.

Feynman delivered a series of introductory physics lectures at Caltech that were later compiled into the renowned textbook "The Feynman Lectures on Physics". These lectures are celebrated for their clarity, originality, and engaging style, and they have had a profound impact on physics education worldwide.

Feynman continued to conduct cutting-edge research at Caltech, mentoring numerous graduate students and postdocs who went on to become prominent physicists. He fostered a vibrant and intellectually stimulating environment within his research group.