Climate change and the resultant requirement to reduce greenhouse gas emissions have become one of society’s main challenges. High emissions occur in the industrial sector and particularly in steelmaking. Due to energy-intensive carbon-based production processes, there is a significant potential to reduce greenhouse gas emissions in the steel industry. In this context, a promising technology is the hydrogen-based direct reduction of iron ore that can be used instead of coal-based blast furnaces. However, the transformation toward sustainable steelmaking implies various regulatory, technological, and economic challenges. For example, decision-makers must decide about strategic investments in the context of an uncertain political environment and unpredictable development pathways of future technologies. These courses have a direct impact on the competitiveness of steelmaking corporations. Consequently, decision-makers in industrial practice waver to design and evaluate advantageous transformation pathways for their corporations. We propose a framework of a decision support tool to design and evaluate the transformation toward sustainable steelmaking. To this end, we model the relevant steelmaking processes based on activity analysis and link them to optimization packages. Decision-makers can evaluate alternative future market scenarios and determine the optimal transformation pathway for their corporation. We discussed our framework with decision-makers from steelmaking. They confirm the effectiveness of our approach to support them in evaluating advantageous transformation pathways for their corporation.