From CFO to COO: How a Finance Leader Mastered the Shift to Operations

The Evolving Role of the CFO

There is a growing trend among finance leaders taking on additional roles, such as chief operating officer (COO), or even combining the responsibilities of both CFO and COO. This shift is largely driven by the expanding scope of the finance chief’s role and the evolving needs of modern businesses.

John Rettig, with over 25 years of experience in strategic finance leadership, has seen the CFO role transform significantly. Currently serving as president and COO of Bill, a finance software company, Rettig’s career reflects the profound changes that have redefined what it means to be a finance leader.

Rettig joined Bill as CFO in 2014 and recently transitioned into his COO role. He was succeeded as CFO by Rohini Jain, who previously held the position of CFO and SVP of Large Enterprise and Merchant Platforms at PayPal.

During an interview, Rettig shared his insights on his move from finance chief to COO. “The impact and influence of the CFO have broadened dramatically compared to 25 years ago,” he explained. Over the past decade, he described this period as the era of “CFO 2.0,” where the role has shifted from merely reporting numbers to acting as a strategic advisor and true business partner to the CEO. “I’ve lived this transition myself, and my peers across tech and growth companies have seen the same thing,” he said.

With the rise of artificial intelligence (AI), Rettig believes we are entering a new era—“CFO 3.0.” According to him, finance chiefs must now have a comprehensive understanding of the technology used by their companies.

The Value of Precision and Execution

Rettig emphasized that the discipline and understanding required to communicate precisely—especially in the high-stakes environment of a public company—are valuable assets when transitioning to a COO role. “You really need to have visibility on execution, understand results, know where to dig deep, and gain a bottom-up understanding of how things work,” he said. This process can naturally lead to operational leadership responsibilities, including partnering with leaders across the business in the age of AI, he noted.

Embracing Change and Innovation

Rettig pointed out that AI is advancing at an “exponential speed,” even compared to just a year ago. “I think the exciting part about that is there’s no longer a status quo,” he said. “AI is coming for everything.” This brings both tremendous opportunities and disruptive threats, he added.

For Rettig, success now requires an attitude of constant reinvention—leaning into emerging technology, experimenting boldly, and never being afraid to overhaul your business model before someone else does. “This is really powerful for the role of the CFO or COO, and the entire executive team,” he said.

Regarding Bill’s AI strategy, Rettig highlights two key areas: customer-facing products that automate complex financial processes and transformative internal improvements. “It’s not just about making work more efficient,” he explained, “it’s about using technology to eliminate work entirely.”

Focus on Execution and Vision

As president and COO, Rettig continues to focus on both short-term execution and long-term vision. During his tenure at Bill, which serves small and mid-sized businesses, the company has grown from 140 to 2,500 employees. His top priorities now include accelerating time-to-market, preparing the organization for future scale through investments in automation and operational efficiency, and ensuring every resource is directed to its highest-value use.

A big part of his role will also be fostering company culture. “I’ve been with Bill for over 11 years now, which is a really long time in a Silicon Valley tech company,” Rettig said. The most important reason he came to Bill was the people. “And I’m still here for that same reason,” he said.