There is an enhanced awareness among the firms regarding the impact of their marketing and business activities on the environment and society largely due to consumer education, the role of activists and aftermath of some disasters. The firms have started to look at these issues in a more holistic manner which is evident from the sustainability practices undertaken by them. In spite of such efforts, their outcomes regarding sustainability efforts are not in line with the expectations, raising the bigger question whether the firms are displaying and enacting right set of behavior towards sustainability. In view of this background, this paper explores the multifaceted behavioral dimension along with its drivers that contribute towards sustainability in a firm. It also endeavours to develop a measure of sustainability for the firms by including behaviour at the firm level as an additional dimension apart from the economy, social and environmental dimension from triple bottom line perspective. The paper also proposes the relationship between sustainability of the firms and performance metrics including marketing metrics. This paper aims to delineate directions for marketers and policy makers with regard to sustainability marketing.