Account Executive plays a big role in advertising agency. They are the front liner in the advertising agency that responsible in maintaining relationship within the external and internal team, they are also the one that responsible for all the process of advertising and campaign from the beginning to the execution MullenLowe Group Indonesia is a marketing and communication agency focused on brand strategy, communication planning and through-the-line advertising which has serve several leaders brands in Indonesia, one of them is PT. XL Axiata. During the internsship, as an Public Relations student, the author implemented the Public Relations and Marketing Public Relations concept to the daily basis as an Junior Account Executive. Throughout the internship, the author realize that the Account Executive job is not just about selling the ideas, implementing marketing communication tools, but an Account Executive have to be able to build and maintain a great relationship and communication within the internal and external team and have a critical thinking ability in conducting a research for the projects to be done as what the clients wish, this actually proven that the concept of Marketing Public Relations are implemented in the daily basis work of an Account Executive at MullenLowe Group Indonesia.