The 23-year-old, who has made five appearances for the Silkmen this season, will be eligible for this weekend’s trip to Bromley.
The former Torquay United captain joined Macclesfield in the summer having made over 100 appearances for the Devon club.
Prior to that, the Jamaican had progressed through the academy systems at Coventry City and Brighton & Hove Albion respectively.
Richards’ loan arrangement will see him stay at The Automated Technology Group Stadium through to Tuesday 12th December.
McDonald said: "Courtney will add energy and quality to our midfield to complement what we already have.
"Despite only being 23, he's an experienced footballer who is a leader and will be a good character to have in our dressing room".