The rise of the economy and industries’ increasing negative impact on the environment and use of its resources has led to unsustainable practices to generate financial profitability. However, climate activists and an awakening from the public and different stakeholders, has led to pressure on companies to integrate sustainable practices and take the Environmental, Social and Governance (ESG) principles into consideration, especially with the official sustainability reporting in the EU. This study aims to analyse the efficiency and effects of ESG reporting and implementation from the perspective of sustainability experts who are actively engaged in companies in different industries. Through interviews, the aim was to find out what difficulties and potential improvements the sustainability experts identified from their experiences and work in different companies and if there were any common factors or variations between the companies’ focus areas. The study was based on Ethnographic Content Analysis of qualitative semi-structured interviews. The theoretical framework is based on stakeholder-, agency, signalling, and legitimacy theory and relates to previous research about sustainability reporting. The results showed differences and similarities in strategies, focus areas on the ESG-principles and the overall sustainability reporting and its implementation. Moreover, all the companies in the study aim to incorporate sustainable practices and alternatives, and implement the ESG-principles to a greater extent in their respective businesses. In conclusion, industries need to improve competence, collaboration and communication to handle the challenges of the Corporate Sustainability Reporting Directive, as well as improve the overall integration of sustainability within the companies.