After setting up the Zendesk for Salesforce integration, is there a way to bring all old (closed) Zendesk ticket data into Salesforce.
There are many variables at play here, so the answer can be a little convoluted. First of all, you should be able to see any tickets using a VisualForce page, as this will simply display all ticket data. However, if you set up a target in Zendesk to be able to map custom fields/objects in Salesforce (especially for reporting purposes), this data can only be sent over with a Zendesk ticket update. As closed tickets in Zendesk cannot be updated, this information would not be available to push on to Salesforce.
There are a few options that you can use to export that data and get it into Salesforce. Here are some options available so you can send your closed tickets from Zendesk to your Salesforce: