In recent times probably Corey Pavin (US Open 1995), and before that most likely Paul Runyan (USPGA - 1934 and 1938). Pavin averaged about 250+ yards with his drives, and the archives indicate that Runyan was around the 220+ yards mark.
Comparisons between the two are a bit hypothetical given the differences in technology.
They were both excellent golfers in their prime and made up for their slight builds and comparative lack of length of the tee with unerring accuracy, canny course management, and great short games (no pun intended).
Chat with our AI personalities