Lewis joins the IoF from London's Voluntary Service Council, where he was CEO. He plans to work closely with the comms team to ramp up the IoF's online presence.
Plans include a new- look website and wider communication with fundraisers on Facebook, Twitter and LinkedIn.
The institute's director of marketing and comms Simon Morrison said Lewis was keen to overhaul the charity's digital and social media comms.
He added: 'We are looking to revamp our online offering so that we can talk to fundraisers directly and effectively, ensuring we can help them deliver as much cash to their charities as possible.'
The IoF aims to communicate among its current members, and encourage new fundraisers, by using forums, audio and video content to promote the work it does.
Morrison added: 'It is important we provide immediate and useful content to our online users on all topics. We must listen to them on major industry issues and doing this digitally is something very exciting, which I know Peter will be keen to execute effectively.'
Lewis' previous experience includes working for national homelessness charity Crisis, and roles as CEO of the London Cycling Campaign and business manager at the Greater London Authority.