I’m fascinated by what makes someone an effective nonprofit leader.

Yes, leaders should be inspiring and visionary, setting and articulating a vision for the organization. And, of course, it’s important for leaders to manage finances well, to be compelling fundraisers, and to be good at delegating responsibilities. But, more than anything, being an effective leader comes down to character, work ethic, and personality.

One way to think of it: an effective nonprofit leader is a person with thick skin, dirty fingernails, and a good heart.

Let me tell you about a woman I’ll call Anna, who has been running a historical museum, and running it extremely well, for many years. She’s an exemplary nonprofit leader. Anna is calm and cool. She resists the temptation to respond to provocations. I was speaking with one of her board members, a historian of the early American Navy, and he said, “Anna’s made of live oak!” His reference was to the remarkably dense framing timber, live oak, that was used to construct Old Ironsides and the other 18th-century frigates of the first U.S. Navy. Live oak gave those ships an unequalled resilience. Anna, he told me, was made of the same stuff. “Cannonballs just bounce off her.”

This is not to say that Anna is unaware of the people and circumstances around her: far from it! Anna certainly notices when a board member makes a snide comment or pursues an unhelpful line of argument. She is not oblivious to bad news. She has lousy days like everyone else. But she doesn’t let it get to her – at least not in a way that people notice. If someone makes an obnoxious comment, she doesn’t take the bait. She assumes, correctly, that bad ideas will fail on their own. She knows that petty comments, unanswered, only hurt the person who uttered them. She doesn’t dig in and fight about the small stuff. She sails on, calmly, head held high, eyes on the horizon.

Some less-grounded CEOs may attempt to emulate Anna, but they fail. Their skin is too thin, their egos too fragile. They’re not made of live oak, but balsa wood. They interpret a board member’s thoughtless comment as an aspersion on their character. A trivial disagreement about a line item in the budget becomes a moral stand-off. Molehills become mountains, then volcanos. They may also get moody and depressed. Instead of reassuring those around them, they inspire worry, even panic.  Relationships with overly sensitive and combative leaders are fraught. People worry about what to say in their presence. There’s less candor, more anxiety. Board members, staff, and the public grow weary of the skirmishes; they distrust the mood swings.

Anna, by contrast, is steady, reliable, and calming.

Anna’s second central characteristic: she has work ethic that puts the rest of us to shame. She’s the first to the office and the last one home. She responds to emails and phone calls almost immediately, and in a personalized way. And she’s not above doing any task. I’ve seen Anna reach into the trash barrels after a board meeting to pull out bottles for recycling. I’ve seen her scurry off to mop up spills in the bathroom. I know it’s important for leaders to delegate day-to-day duties: in fact, I often counsel CEOs not to get caught up in small tasks that others can do just as well, or better. But it’s also important to lead by example. When the CEO works long hours and grabs a mop to clean up bathrooms, the rest of the staff takes on the same attitude. They certainly can’t put themselves on a pedestal and sniff, “But that’s not in my job description!”

Finally, and most importantly, Anna has a great heart. Her staff adores her. “She’s a great mentor,” they say. “She always has our backs.” “She encourages me to grow professionally.” “She lets me figure out how to do a job, and she always remembers to compliment me.” “If something doesn’t go as planned, she doesn’t throw us under the bus.” And whenever anyone praises Anna, she inevitably redirects the credit to her staff. “They’re remarkable! The staff are what make this place great!”

Studies show that the single most important factor in job satisfaction is the employee’s relationship with the supervisor. Yes, salary and benefits matter, and they should. But in the end, how people are treated by their boss is the biggest determinant of happiness in the workplace. I’m in the middle of a conversation with a good friend who’s done remarkable work raising money for his institution, but he’s leaving because his supervisor micromanages and belittles him. On the other hand, nobody ever wants to leave Anna and her museum.

When organizations are searching for a new CEO, they understandably focus on credentials: degrees, job experience, and expertise. But what’s even more important is the person’s character. CEOs with all the credentials in the world will sink if they are aloof, have fragile egos, and are driven by a quest for personal glory. If they take offense at real or imagined slights, they won’t be successful. If they ignore the staff and make it all about themselves, they’re doomed, and so is the institution.

So, yes, study the resumes and CVs. Compare the credentials. But, all things being equal, I suggest that you hire the person whose character is carved from live oak.