Eric Ries founded CatalystRecruiting as an undergrad, worked as an engineer for a few years, and then co-founded and was CTO of IMVU, which had a string of internal failures followed by perseverance and success. His experience there seems to have formed the core of the Lean Startup book.
Straight from Steven Blank's personal bio: "After 21 years in 8 high technology companies, I retired in 1999. I co-founded my last company, E.piphany, in my living room in 1996. My other startups include two semiconductor companies, Zilog and MIPS Computers, a workstation company Convergent Technologies, a consulting stint for a graphics hardware/software spinout Pixar, a supercomputer firm, Ardent, a computer peripheral supplier, SuperMac, a military intelligence systems supplier, ESL and a video game company, Rocket Science Games. Total score: two large craters (Rocket Science and Ardent), one dot.com bubble home run (E.piphany) and several base hits."
Don't write somebody off as an academic just because they've written a book.