Block served as the company's vice chairman, president and a director since joining Salesforce in June 2013. He has been the company's COO since February 2016.
Block will work alongside co-CEO Marc Benioff, who will remain the Chairman of the board. While Benioff will lead Salesforce's vision and innovation, Block will look after the company's growth strategy, execution and operations.
Salesforce also appointed its co-founder and Chief Technology Officer Parker Harris to the board, it said in a separate statement.
— CNBC contributed to this report.