“It really wasn’t me- all credit goes to my great team.” How often have we heard that line from a leader, or used it ourselves? We admire that manager’s humility and assume anyone using that approach must be great to work for. Right?

Former Secretary of State Colin Powell doesn’t think so. He used to tell his senior staff at the State Department, “If your team did all the work, then why do I need you?” He would say this with a tinge of humor, but his point was clear: leaders need to lead, and their contributions ought to amount to more than just the sum of a team of followers, even if that team is high-performing.

Powell brought the U.S. Army culture—where he served for 46 years, ultimately as Chairman of the Joint Chiefs of Staff—with him to the State Department. He realized that one of the most challenging aspects of his new role would be to reshape the culture of the department to serve his vision for American policy. And he would have to dig in and take the lead, not simply rely on those he had assembled around him. Changing the culture of an organization may be the toughest assignment any leader will confront.

Powell knew this and so did Alan Mulally, who took over Ford Motor Company on the eve of the 2008 financial meltdown. As Bryce Hoffman recounts in his 2012 book American Icon, Mulally took his decades of experience building a culture of teamwork at Boeing and slowly massaged it into the strong and independent spirit of the American auto industry. He required that those who had previously isolated themselves integrate into the collective. That decision paid off; Ford was the only automaker to avoid bankruptcy after the American economy collapsed. Collaborative leadership and shared problem-solving won out over older models of Detroit leadership.

I experienced the challenge of organizational culture change directly when I assumed the leadership of Population Services International (PSI) in 2007. Before I arrived, PSI had harnessed the power of an individual-driven culture to fuel the organization’s expansion in the decades since its founding in 1970. The high-performing PSI staff, however, was proud of its iconoclasm in a sea of cooperative NGO partnerships, where rewards often favored showing up more than getting things done. PSI embraced its cowboy reputation, anxious to wade in and do things while others dithered in working groups.

But in 2007, expansion powered by a strong culture of individualism was showing its limits. As the emphasis on collaboration in the global health community grew stronger, PSI’s autonomy became an obstacle to growth, rather than an attribute. Suddenly, institutional funders in the realm of global health required active partnering among grant recipients. One of PSI’s leading donors, The Global Fund to Fight AIDS, Tuberculosis and Malaria, began gathering stakeholders and cooperating implementers at the same table to decide how to execute grants. Increasingly, major donors like USAID expected large consortia of NGOs to bid on larger projects together.

For PSI, a funding landscape that rewarded collaboration over individual success challenged the status quo. PSI’s staff had always prided itself on the entrepreneurial energy and independence at the ground level, “where the health happens.” Headquarters management exercised relatively little direction over country-level decisions, which was considered an organizational strength. But PSI was growing as well, managing even more programs in multiple countries funded by multiple donors. The growth was challenging PSI’s individualism, opening up organizational risks and fatigue created by perpetually reinventing-the-wheel, due to the absence of effective organization-wide systems. For instance, human resource systems varied widely across the countries in which PSI worked and financial reporting had not yet been standardized.

I termed this a mismatch between PSI’s “muscle mass,” our field programs, and our “skeleton,” or the procedures, policies, and systems needed to make that muscle mass perform at its highest levels. PSI needed to shift its culture toward greater centralization and standardization, without sacrificing its independence and spirit of innovation.

We began by introducing a new enterprise resource planning system, with change management components built in. At first, this was badly received, but over time PSI developed its own homegrown approach using innovation tools that have worked consistently. We began hiring with a broader definition of the skill sets we needed, rather than solely those typical to global health. We inventoried our policies and procedures, built structures to vet and approve new ones, and we rewarded leaders who upheld these policies, actively embracing a culture of collaboration. While these changes did expand the organization’s bureaucracy, it also led to more buy-in. We overhauled our corporate mission statement and embraced six refreshed corporate values, which emphasized that success comes from honest and pragmatic work with others for long-term sustainable impact.

These changes—toward collaboration and away from individualism; toward standardization and away from bespoke systems everywhere—are incomplete and uneven. And I must take care of course not to push such changes too far because there is much positive energy in PSI’s legacy culture, which deserves to be nurtured. Nonetheless, the organization’s cultural shifts over the last eight years have enabled PSI to double in size, expand its range, and deepen its impact.

Across the public, private, and social sectors, different leadership ideals prevail—even practices that seem to be diametrically opposed have been successful in the right circumstance and context. In the business world, influential leaders like Elon Musk, the late Steve Jobs, and Jack Ma have met with great success through top-down approaches, while Sheryl Sandberg, Paul Polman, and others have delivered incredible results through collaborative and shared-leadership models. In government, a culture of global insecurity and persistent challenges often favor executives willing to make unilateral choices. Yet, the complexity of today’s interdependent world and the need for collective security can also favor more subtle models of leadership such as what the Obama administration informally termed “leading from behind.” In the social sector, one can cite numerous examples of successful and highly individual leaders who have presided over strong growth and impact, though the sector itself has often embraced collaboration and shared approaches to challenges more consistently.

In reality, both Colin Powell and Alan Mulally’s lessons on leadership hold true in a complex landscape of leadership for positive change. Leaders shape the future of their organizations, more than just simply by building the right team, and the absence of a strong and appropriate culture can prevent an organization from achieving its goals, no matter how adept its leadership may be. Leading enduring approaches to social impact demands patience, commitment, and the wisdom to adapt to the conditions the marketplace of the future will reward.