Think back to the best leaders you’ve had, whether at work or elsewhere. What do they have in common? Compassion? Intellect? Humor? Experience on the organization’s “factory floor”?

The bosses I look back on fondly had all those things and more. But by comparing them to the weaker ones I’ve worked under, I’ve come to believe there’s at least one more critical leadership trait: a sense of self.

Signs of a Self-Secure Leader

Why would a strong self-identity matter when leaders should be serving others? Because our self-identity dictates not just how we see ourselves, but also how we interact with the world. In my experience, leaders with a strong self-identity tend to be:

1. Consistent
There’s nothing more frustrating or, frankly, wasteful than a manager who changes his mind on a whim. The leaders I’ve had whose self-identity seemed weak struggled to finish projects, flitting from technology to technology and trend to trend. Those I’ve had who knew themselves also knew what they wanted to accomplish, and they aligned their actions with it.

That’s just my observation, but it does fit well with role theory, an increasingly popular psychological and sociological framework. In “Reconstructing Strategy,” Dr. Saqib Qureshi points out that we internalize our identity’s story and meaning through our behavior. Someone who sees himself as an ethical leader, for instance, is unlikely to throw a teammate under the bus because doing so wouldn’t align with who he thinks he is.

2. Motivated
Enterprises spend thousands on industrial psychologists, hoping to uncover cost-effective ways the company can motivate its workers. Although most theories of work motivation encourage employers to find ways to maximize the employee’s reward through “carrots” like free office snacks, self-concept theory says that an individual’s motivation is dictated at least in part by internal, individually rooted needs.

It might seem counterintuitive, but people who care more about their own needs tend to be more self-secure — and better leaders — than their peers. The reason is that putting one’s own needs first requires not just an understanding of, but also a belief in, the validity of those needs. Now, consider the needs typically associated with leadership: achievement and social acceptance. Subscribers to self-concept theory say self-secure leaders work hard not just because it leads to external rewards, but also because it fulfills their conception of themselves as achievers and team players.

3. Empathetic
Empathy is another trait you might not associate with a strong self-identity. Shouldn’t people who are less focused on themselves be better able to connect with others? That hypothesis was the very one University of Missouri neuropsychology professor Brick Johnstone held before he studied the subject. After scanning participants’ brains with an MRI, however, he found that more empathetic individuals displayed more activity in an area of the brain tied to their sense of self.

How did Johnstone explain his findings? If someone doesn’t have a clear sense of who she is, he suggested, then she’ll likely struggle to imagine what someone else is experiencing. Just how important is that for leaders? When executive recruitment firm Egon Zehnder International studied the subject in senior executives, it noticed that the most emotionally intelligent individuals were more likely to succeed than those with a higher IQ or more relevant experience.

“Know thyself” may not be a new maxim, but researchers are just beginning to recognize its importance when it comes to business. Those of us in the trenches, however, need only look at the leaders we’ve worked for: The ones who deserve the title learned to lead themselves before they ever began leading others.