John Watson is a common name. Some of the more notable John Watsons include:

• John Watson, psychologist (1878-1958), pioneer of behaviorism
• John Watson, race car driver for McLaren who won the 1981 British Grand Prix at Silverstone [1] http://www.mclaren.com/history/drivers/johnwatson80s.htm
• John Watson , chess player and author
• John Watson, VC, recipient of the Victoria Cross

Also

• John Watson, M.D., fictional sidekick of Sherlock Holmes