Procter, who joined The Independent three years ago from its sister regional operation, is returning to regional newspapers as the managing director of the sales operation Mediaforce.
He will work out a six-month notice period and The Independent will announce Procter's replacement later in the year.
Separately, The Independent has hired Andrew Christie, the former News International strategic planning director, as its group strategy director with a focus on advertising.
Terry Grote, the managing director at The Independent, is heading an initiative to change the way the paper sells its advertising by introducing a more proactive approach and increasing emphasis on clients and media planners.
This follows problems with media agencies regarding the pricing structure introduced when the title went compact last September.
Procter has promoted Simon Cooke and Jo Redfern to the roles of advertisement directors for display and classified respectively.
The Independent wants advertising revenue increases to keep pace with circulation rises since it went compact. In its first month as a fully compact title, The Independent posted a June circulation of 261,575, an increase of 18.8 per cent year on year.
Procter said: "I've achieved what I wanted to achieve here and am leaving at a fantastic time. The paper is in brilliant shape so one job is finished and another is about to start."