React Material UI: How to give a button a custom color when disabled?

Or you can try createMuiTheme and customize the following property:

import { createMuiTheme } from '@material-ui/core/styles'

const theme = createMuiTheme({
  palette: {
    action: {
      disabledBackground: 'set color of background here',
      disabled: 'set color of text here'
    }
  }
}

You can define a class to be applied for disabled buttons:

const styles = theme => ({
  disabledButton: {
    backgroundColor: theme.palette.primary || 'red'
  }
});

And then, use it like this:

<Button
  variant="contained"
  color="secondary"
  disabled
  classes={{ disabled: classes.disabledButton }}
>
  Disabled
</Button>

You can find in the documentation all the classes that you can override.