I was going crazy trying to figure out how to get rid a face I accidentally created. Not very obvious answer, you need to do a Command-Delete.
To remove a person from your corkboard:
- Click to select Faces in the Source list.
If you’re in full-screen view, click the Faces button in the toolbar. If you don’t see the Faces button, click the button in the top-left corner of the window one or more times, until you see the toolbar change to the right one. Learn more about using the toolbar in full-screen view.
- Select the Faces snapshot you want to remove, and then press Command-Delete.
- Click the Delete button in the dialog that appears.If you change your mind before taking any other action in iPhoto, you can place the person back on your corkboard by choosing Edit > Undo.