Should you "hide" your earlier professions?


An HR professional, who had hired for my team, moved on to another company. There, he switched to a different profession. During a casual conversation, when I mentioned his hiring expertise, he said something as if I never knew him before: "No, I'm not an HR expert. Actually, I ..."

This guy perhaps wants me to forget him as a former HR professional. He believes that he should build his personal brand around his current new profession/discipline. I appreciate it because I've had my own similar experiences. In terms of disciplines, I moved ...

From Technical Writing in the 1980s (here, I innovated a software usability driven approach, which I published and presented at conferences) ...
To User Interface Design (here, I innovated a business process centric approach, which differentiated former employer Cognizant Technology Solutions and gave the company competitive edge right from its early days) ...
To Business Process Management (here, I created a business process centric software approach, a brief note about which you'll find at the Columbia Business School website).
Not only was I moving into different disciplines, within each discipline, I was "moving into" a different approach.

At each move, I wanted to eliminate the potential for confusion with my previous profession/approach and wanted to strengthen my current brand.

Excellence guru Tom Peters, who is also master of personal branding, says in Re-Imagine:
"I was very proud, I tell you, of the persona called ... California Tom. And quite willing to bury Maryland Tom back in Maryland."
If you have switched disciplines, how did you deal with the associated challenges?

PS: By talking about my earlier disciplines/approaches, have I confused readers about who I am today?