Born in Philadelphia, George went to sea at age 16, before settling in California. After a failed attempt at gold mining he started to work his way up through the newspaper industry, starting as a printer and ending up an editor and proprietor.
On a trip to New York George was struck by the apparent paradox that the poor in that long established city were much worse off than the poor in less developed California. This paradox supplied the theme and title for his 1879 book, Progress and Poverty, which was a huge success, selling over 3 million copies. In it George made the argument that nearly all of the wealth created by social and technological advances is captured by land owners via rents, and that this concentration of unearned wealth is the root cause of poverty.
George was well placed to discover this pattern, having experienced poverty himself, knowing many different societies from his travels, and living in California at a time of rapid growth. In particular he had noticed that the construction of railroads in California was pushing up land values and rents as fast or faster than wages were rising.
Progress and Poverty and its successors made Henry George the third most famous man in the USA, behind only Mark Twain and Thomas Edison. He was much in demand as a speaker, particularly in places such as Ireland and Scotland where access to land was (and still is) a major political issue, and he made several speaking trips abroad. His ideas were taken up to some degree in South Africa, in Taiwan, and in Australia, where state governments still levy a Land Value Tax, albeit low and with many exemptions. An attempt by the Liberal Government of the day to implement them in 1909 as part of the Budget caused a crisis in Britain which led indirectly to reform of the House of Lords.
Given his popularity while alive Henry George is surprisingly unknown today, however there are still many Georgist organisations in existence and many people who do remain famous were heavily influenced by him, such as George Bernard Shaw, Leo Tolstoy, Sun Yat Sen and David Lloyd George.