As with everything in Photoshop, there are oodles of ways to achieve this. The simplest would be to paint over the relevant areas with the Blur and Sharpen brushes, but they give you all the control and finesse of a hammer. Much better to do it with a little precision.
First, duplicate the image layer twice:

It's a good idea to rename them to avoid confusion:

Hide the "Blur" layer and select the "Sharpen" layer:

Apply sharpening as needed. Of course I had to sharpen outrageously for this one; usually that won't be the case:

Everything is sharpened now, which isn't desirable ...

... so add a layer mask and reveal only the subject's features:

Turn on the "Blur" layer and copy the layer mask from the "Sharpen" layer; then invert it so the subject is hidden:

Then apply an appropriate amount of blur.

That should do it. Here's the original compared to the "false focus" result:



