Many people have contributed to developing and promoting the use of regular expressions since they were invented about half a century ago. Here's a short list of some of the most influential people behind the technology. I've written this up for two reasons:
- For people who've only gotten into the technology recently but are interested in some of the history and pioneers behind it.
- Since I fit the above description, I'm hoping readers will help fill me in on other people I've forgotten about or otherwise left out.
Alfred Aho
Aho is the "A" in AWK, and co-author of the Dragon Book – a classic reference covering such topics as building regular expression compilers. He created the initial version of egrep, which provided a big jump in expressiveness from the primitive beginnings of early Unix grep.
Websites: Wikipedia, @Columbia U (photo source)
Jeffrey Friedl
Friedl began using regular expressions with Unix in 1980. He has since written the definitive work on the subject: Mastering Regular Expressions, published by O'Reilly Media. Now in its third edition, it is widely considered a classic programming book (see e.g. this Slashdot review). The longevity of his experience with regexes helps to make him a shrewd opponent in regex debates… odds are he's already succinctly countered your quackery ten or more years ago on Usenet, and has the links to prove it. 
Friedl lives in Kyoto, Japan with his family of three.
Websites: Blog (photo source), O'Reilly bio
Jan Goyvaerts
Goyvaerts – a Belgian who's been living in Thailand for several years – is not as widely known as the others on this list, but his contributions towards helping thousands of people learn and use regular expressions are significant. Goyvaerts creates the best-in-class tools RegexBuddy and PowerGREP, which use his own JGsoft regex engine (notable for its support of most syntax from popular regex flavors including Perl, .NET, and Java). His website regular-expressions.info – based on the PowerGREP/RegexBuddy help files – is the best and most popular multi-flavor regex tutorial or reference online.
Edit: A year after this post, Jan and I coauthored Regular Expressions Cookbook, now in its second edition.
Websites: Regex blog, Just Great Software (photo source)
Philip Hazel
Hazel grew up in South Africa and has a PhD in applied mathematics. He's best known for writing Exim (a popular open source mail transfer agent) and the PCRE regex library. PCRE is one of the best regex libraries in the world and is used by many projects including Apache, PHP, and probably thousands more. Hazel worked for the University of Cambridge's Computing Service for over 30 years until he retired at the end of September 2007.
Websites: Personal site, UIT Cambridge bio (photo source)
Stephen Kleene
In the 1950s, distinguished American mathematician Stephen Kleene invented regular expressions, which is what he called his notation for expressing the algebra of regular sets. The regex * metacharacter (called the Kleene star) is named after him. Kleene helped lay the foundations for theoretical computer science through his work on recursion theory, which resulted in him being awarded the National Medal of Science in 1990.
Websites: Wikipedia, Bio at nap.edu (photo source)
Henry Spencer
Spencer is a Canadian programmer and space enthusiast who created three widely used, adapted, and influential regular expression libraries. In 1986, he was the first to release a regex library which could be freely included in other programs. Perl 2's regex package was based on and enhanced from Spencer's library, but Spencer's technological tour de force was creating the regex package used by Tcl. This implementation, Jeffrey Friedl writes, "is a hybrid [NFA/DFA engine] with the best of both worlds".
Websites: Wikipedia, O'Reilly bio, Lysator, Bio at NASA (photo source)
Ken Thompson
Thompson is a hacker demigod and the principal inventor of Unix. He received the Turing Award in 1983, the National Medal of Technology in 1998, and the IEEE's Tsutomu Kanai Award in 1999. Thompson introduced regular expressions to the computing world by building Stephen Kleene's notation into his version of the QED text editor, and later ed and other tools. Thompson's original regular expression search implementation is still considered by some to be superior to modern, backtracking algorithms. Did I mention this dude flies MiG fighter jets for fun?
Websites: Wikipedia, Linfo, @Bell Labs, Bio at Bell Labs (photo source)
Larry Wall
Wall created and continues to oversee development of Perl, which has done more than any other programming language to popularize and extend the power of regular expressions. Many programming languages including Java, JavaScript, the .NET Framework, PHP, Python, and Ruby have since adopted regex syntax and features similar to Perl's. The recently released Perl 5.10 continues to push the state of the art in regex power, and upcoming changes outlined by Wall for Perl 6 (called Perl 6 rules; described in Apocalypse, Synopsis, and Exegesis 5) fearlessly redesign Perl's regular expression language.
Websites: Personal site, Wikipedia (photo source)
I'm still a newcomer to the field, so please let me know if you think there are others who should be on this list.