In his new position, Knowland will take over the duties of Ian Pearman, who was promoted to managing partner in October.
Knowland will be replaced by the board account director Deborah Kerr, who will take responsibility for marketing and new business.
This year, AMV has picked up two major accounts: RAC, which was worth £10 million and won without a pitch, and the £10 million SwitchCo account, which it retained this week after a second pitch.
It also retained two of its biggest accounts, the £37 million Sainsbury's business, after a final pitch against JWT, as well as its BT business.
Kerr joined AMV from TBWA\London in July 2003 with a brief to run the Sainsbury's account. She then moved across to take control of Camelot and Yell.
Kerr began her advertising career at Leo Burnett, where she worked on Procter & Gamble and Kellogg, before moving to Bainsfair Sharkey Trott.
After the merger with TBWA\London, Kerr became the managing partner of the agency.