Despite all of his recent on-water activity, Knox-Johnston is most widely recognized for his participation in the 1968 Sunday Times Golden Globe Race, in which he bested eight other sailors to return home after 312 days alone at sea. The race has been well documented, in both the popular book AVoyage for Madmen by Peter Nichols and a documentary, Deep Water, released in 2007. The 1968 race represented one of the last frontiers of human conquest, with nine entrants racing to be the first to solo circumnavigate the world without stopping. While a few dropped out early when their boats encountered issues, it was Donald Crowhurst, Bernard Moitessier, Nigel Tetley and Robin Knox-Johnston who became the focus of a media spotlight not often witnessed in the yachting world. Crowhurst famously tried to fake his voyage after he realized his boat was ill-equipped for open seas, eventually abandoning it and committing suicide. Moitessier decided to leave the race altogether, opting to continue his voyage another two thirds of the way around the world again, finally landing in Tahiti. Nigel Tetley would have won the prize for the fastest circumnavigation, but his multihull broke apart and took on water, sinking 1,300 miles from his final destination.

Knox-Johnston was the only entrant to finish the race, 313 days after his departure and a month after his 30th birthday. He donated his winnings to the family of the recently deceased Donald Crowhurst.

The fact that Crowhurst committed suicide and Moitessier kept sailing led many to believe that solo ocean racing was a gateway for mental instability. But the unequivocal sailor Knox-Johnston dispels this idea, calling the thinking “trite.” With perfect memory he recites Matthew 7: “Judge not, that ye be not judged. For with what judgment ye judge, ye shall be judged: and with what measure ye mete, it shall be measured to you again.”