- Try a tool like Deckset which can take Markdown and generate Keynote presentations. Deckset was designed specifically for this purpose and has features like presenter notes and themes built-in.
- Write your content in a text file using Markdown formatting for the slide titles. Then copy and paste the slide titles manually into Keynote to create the presentation outline. You’d have to manually add speaker notes and images, but the titles would be there to get you started.
- Use a combination of automation and manual work. For example, use Pandoc to convert the Markdown to HTML slides. Copy the slide titles from HTML into Keynote. Then write the presenter notes and add images manually. This takes more work but may give you more control.
The key advantage with Keynote is the ability to have presenter notes only visible to you in presenter mode. To replicate this fully from Markdown, a tool needs explicit support for presenter notes. Deckset is designed for this while Pandoc would get you part way there. With some manual effort you can take Markdown content and turn it into a nice Keynote deck.