A senior copywriter is an experienced copywriter at an ad agency or marketing company. Your duties and responsibilities are to collaborate with the associate creative director or creative director to develop compelling copy for ad campaigns and marketing pushes. You develop written content to meet the client’s needs or wants for their campaign and ensure the tone corresponds with the visual and campaign messaging. You present drafts to your supervisors, who may recommend changes before deciding on the finished copy that will be used to advertise the product.