If CFOs think they have a lonely job, they should go talk to their CEOs. There are not many people a CEO can turn to for sharing questions or doubts, or to get frank answers to tough questions. Here is where CFOs can make their mark. Looking back at my own experiences working closely with CEOs, I believe CFOs are best positioned to be the CEO’s right hand, the person the CEO can trust to have informed opinions on company issues and candidly discuss the business. Typically, nobody understands the entire company quite as well as the CFO.

But CFOs don’t earn their CEOs’ trust automatically. Being the kind of CFO that CEOs really want—not just need—to help them drive their vision has to start with putting yourself in a position of knowledge and trust with the CEO. And to establish a strong relationship with their CEO, CFOs need to learn their CEOs’ working and communication styles. That’s fundamental to having an honest and open dialogue.

Positioning yourself to have those kinds of frank, detailed discussions about the company with the CEO requires CFOs to perform a range of roles and have certain traits and capabilities. First is being able to understand what your CEO is about— their personality, priorities, operating style and, how they want you to communicate with them. The CEOs I worked with had their own ways of operating and working, so I learned how to flex my communication style to theirs, seeking opportunities for frequent, exploratory discussions to gather information and build trust and understanding.

I made sure that whenever I went in to speak to the CEO, I had a list of items I felt were important to discuss. I would ask a lot of open-ended questions about matters that might be concerns of mine, about what the company was doing or not doing, even if it was something the CEO was pushing for. I would start by saying, “I see this happening and I am a little concerned about it. What are your thoughts?” I found the CEOs appreciated having a CFO willing to express an informed opinion that perhaps they didn’t agree with because it helped them see other points of view as they weighed what was best for the company.

Establishing the trust and rapport with the CEO that enables an open discussion of company issues is only the beginning, or foundation, of what CEOs need from their CFO.

Based on my experience, CEOs seek in their CFOs someone who can be:

• An adept influencer. Sometimes CFOs have to play the “Dr. No,” enforcer role, but they have to be team players, too, to help operating peers make the right decisions and understand the implications of their decisions for the whole company.
• A strong communicator. You’ve got to be a great communicator to your CEO and your board, Wall Street, credit analysts, and employees of how the financials tell the company story.
• A tireless change agent. As a CEO once told me, “organizations develop a lot of antibodies to change.” Companies often develop a strong cultural dynamic opposed to change and the CFO needs to help the CEO continuously drive change.

Of course, CFOs have to go beyond these roles and do the following, at a minimum, to be a credible voice and earn their CEOs’ trust:

1. Understand the business and the strategy and build strong relationships with business leaders. To identify and discuss the company’s strengths, challenges, and gaps, CFOs need to know the business and the strategy as well as the CEOs do and should have solid relationships with the business leaders.
2. Get the right things on the CEO’s radar. CEOs often have more on their plates than they can handle. Especially in this business environment, when companies need to transform themselves and change direction quickly, CFOs need to help the CEO focus on the biggest priorities.
3. Be independent-minded and supportive. My CEOs counted on me to be the truth teller, to form my own opinions on important company decisions and to speak up. At the same time, they expected my support for execution.
4. Challenge the business. CFOs are in the best position to call attention when the numbers aren’t supporting the strategy. For example, CFOs can push the business to change capex priorities when the underlying ROI assumptions are no longer supported by the numbers.
5. Do the blocking and tackling. To make good decisions for the company, CEOs rely on the CFO to have the financial reporting, controllership, and accounting under control.
6. Have a great bench. CEOs—and boards—expect CFOs to have capable finance leaders-in-waiting and a succession plan in place.
7. Offer solutions. The CEO doesn’t expect you to have all the answers, but he or she needs a right-hand person who not only points out problems but proposes possible solutions to spark the debate.

Depending on what kind of CEO you have, you may emphasize some of those roles and activities over others. A CFO who’s more of a visionary may want you to be their truth teller to hold them accountable to the numbers, while a CEO who’s more of an operator may value how you use your understanding of the business and the strategy to drive change. A key to being the kind of CFO your CEO needs and wants is to understand what drives his or her agenda and use your strengths to help execute that agenda, while standing firmly by your own beliefs.