The present invention is directed to a system and method for SAS PHY dynamic configuration which allows for attaching SAS devices having various width ports. Each PHY is configured to be a narrow port internally to the controller while PHYs for the attached device is configured to be a wide port externally to the controller. As such, new SAS devices may be attached without any external controller intervention to reconfigure PHYs to match the new SAS devices. The present invention may allow for the flexibility of designing a single initiator solution that can adapt to any number of SAS devices with any number of port widths. Additionally, the present invention allows for a single product to be released that can automatically adjust to a broad range of SAS solutions and SAS topologies.