The purpose of the undertaken study is to examine the effectiveness of online digital media advertising as a strategic tool for building brand sustainability. For this purpose, we investigate the impact of different channels of online media, such as email marketing, mobile phone marketing, search engine optimization and companies’ websites, and social media marketing for the effectiveness of online digital media advertising. Moreover, the researchers have introduced eight mediating variables and six moderating variables to examine the impact between exogenous variables and online digital media advertising (endogenous). The researchers have taken 910 responses through a modified questionnaire and employed quantitative research methods, such as the structural equation modeling, exploratory factor and confirmatory factor analyses, and Hayes process approach for examining the mediation and moderation amongst the variables. The results of direct impact have demonstrated that all of the channels of digital media advertising have a positive and significant influence on the effectiveness of online digital media that creates brand sustainability for fast moving consumer goods (FMCG) and services sectors of Pakistan. The outcomes of hypotheses pertaining to the mediating and moderating effects of different variables have shown the significant influence between exogenous variables and endogenous variable. The results of the undertaken study are beneficial for the existing literature that provides the basic foil for future research studies. Moreover, the results have significant industrial implications for the marketers and digital media managers that they can devise effective media and marketing strategies to maintain optimum market share and competitive advantages.