knowyourphrase.com - The Meanings and Origins For Several Common Idioms and Phrases
Supporting what you say, not just with words, but also through action or evidence.
This phrase implies that a person should back up their talking with action. For example, a person may gloat about being capable of performing fifty push ups in one go. However, someone who has their doubts might ask this person to "walk the walk," which essentially means prove it to me by doing it, not just by talking about it.
ThePhraseFinder states that the earliest usage of this phrase comes from the Mansfield News, an Ohio newspaper printed in June 1921. There a line from the newspaper which reads:
"Although he has no gilded medals upon his bosom, Howard Herring of the North American Watch
company, walks the walk, and talks the talk, of a hero today."
* You keep bragging to me that you can do forty pushups without breaking a sweat, but how about you walk the walk instead of talking the talk?
Note: A phrase's origins are, much of the time, completely unclear. The origins you see listed are the plausible theories floating around for how or where an idiom came from, but may not necessarily be accurate. The quotes which have the phrase in them are the oldest written forms of the phrase I could find, but keep in mind that older recordings are probably out there somewhere. If you find an earlier citation than what I have, feel free to let me know!
Also, remember that just because you see a saying in an old book or newspaper, let's say from the year 1893, it does not mean the saying originates from that source. In all likelihood, if an expression is already in use in a book or newspaper, then it's probably older. Nevertheless, these old quotes serve as a way to show the reader how far back in history some of these sayings go.