You can manually create a custom Gantt chart from scratch using the native Chart menu of PowerPoint. In its Chart menu, you can find several types of standard charts including line, bar, area, pie ...

Click the option button labeled "Create from file." Click "Browse." Navigate to and select the organization chart Office file. Select "Open" to put the chart into the PowerPoint presentation.

The SmartArt graphic feature offered in Microsoft Office can create an Organization Chart in Microsoft Excel, Word, PowerPoint and Outlook.