(covers information from several alternate timelines)
Golf was an outdoor Earth game that was played by Humans (particularly Human doctors) for several centuries. The object of the game was to sink a ball into a series of holes, using special clubs to drive the ball towards the holes in the least number of strokes. During the late 2370s, The Doctor took up the hobby in effort to follow up on the tradition. Starfleet officer Reginald Barclay also had an affinity for the game.
During a visit aboard the USS Voyager by a holographic Reginald Barclay, The Doctor requested that they might perhaps play nine holes either on the "back nine" on Gedi Prime or Pebble Beach at sunset. Barclay, however, attempted to avoid The Doctor's tee time by having Seven of Nine teach him kadis-kot. (VOY: "Inside Man")
In Tom Paris's altered version of the The Doctor's holonovel Photons Be Free the EMH was upset that he was going to miss his tee time due to his medical assistant's supposed lateness. (VOY: "Author, Author")