S Removing the delay (so just callback() ) doesn't work, the input doesn't get focused.

I have provided the wrong sandbox link, this should be the example: https://codesandbox.io/s/km945lzkzo The input should be focused immediately after the component re-rendered with disabled to false. In your second codesandbox, you have a delay of 100ms, which is undesirable. Furthermore, if the re-rendering took > 100ms, you might call .focus before the re-rendering happens.