Corvin moves up from director of structural design and innovation to head the consultancy after five years as an executive director. He joined SiebertHead as a senior account director in 1999 and has also held the post of client service director.
Before joining SiebertHead, Corvin worked for Design Bridge and Lippa Pearce.
Current managing director Parsons, who has held the position since 1989, will remain a shareholder of the company.
Parsons said: "Tim is ideally placed to develop the company and relishes the challenges ahead. With his proven track record of developing business for SiebertHead, together with his client servicing experience, business acumen and brand development expertise, he has the right mix of skills to take the company to another level."
SiebertHead's client list includes Pepsico, Heineken, ICI, Wrigley, Ferrero and Carslberg.
This month the company launched the Invenio wine range it created for Carlsberg.