He joins the club from Lewes, where he coached the under-18 team last season and replaces Sammy Donnelly, who left as EP manager at the end of last season.
Ettridge has previously coached the senior teams at Steyning Town and Lancing and played in the Ryman League for Worthing and in the Sussex County League for Shoreham, Southwick, Lancing and Mile Oak.
East Preston football Chairman Terry Doyle said: “We are delighted to welcome Paul to EP.
“We were looking for a coach determined to prove themselves at first-team level in the County League and to work with us to rebuild the football infrastructure at the club.
“We have first-class facilities at EP and we are determined to attract good local players and move up to the Ryman League. We are confident Paul will help us to move the club forward.”
Ettridge said: “This is a great opportunity to work with a club focused on progressing both on and off the field.
“I have already spoken to a number of good players about EP and I am confident we will attract a strong group of youth and experience, which will bring success on the field.”