The session implicit object in JSP allows developers to track client sessions across requests. It is an instance of HttpSession that can be used to set, get, or remove attributes and get session information. For example, a JSP page can set a user attribute in the session after form submission, and another JSP page can retrieve that attribute to greet the user by name across multiple pages of a session. The session object behaves the same way as in Java Servlets and is used to maintain state for a client across HTTP requests.