Is there a way to disable the default calendar app on a Samsung Galaxy S4?
Assuming your end goal is just to get the app to shut up (i.e. not get double calendar notifications for all events), all you have to do is disable the alerts and notifications from within the app itself.


Go into the App 
Press the menu button 
Choose Settings 
Scroll to the bottom 
Change Set alerts &amp; notifications to off


For good measure, I also unchecked Vibration and set Select ringtone to Silent, but that probably wasn't necessary.

The app will still be on your phone, but aside from the icon being there you won't even notice it unless you open it.