Imagine inheriting a 45-year-old company founded by your father—a company synonymous with leadership development, a company that literally wrote the book on behavioral interviewing and assessment centers. Now imagine knowing that the entire industry will be watching to see if you’ll preserve the legacy or break it.
Tacy M. Byham didn’t have to imagine it. She lived it.
In 2015, when she became CEO of Development Dimensions International (DDI), she inherited more than just a company. She inherited a philosophy, a methodology, and the weight of expectation that comes with being the daughter of William C. Byham, the industrial/organizational psychologist who co-founded DDI in 1970 and revolutionized how the world thinks about leadership assessment.
A decade later, DDI has been named a Top 20 Leadership Training Company by Training Industry for fifteen consecutive years. It’s recognized by Kennedy Consulting Research & Advisory as the #1 leadership development provider. It operates in 90+ countries and develops more than one million leaders annually. Under Tacy’s leadership, DDI has achieved recognition on Forbes’ 2024 and 2025 America’s Best Employers lists.
But here’s what makes her story remarkable: she didn’t just preserve the legacy. She transformed it.
Earning It the Hard Way
When Tacy joined DDI as a consultant in 1996, she could have coasted on the family name. Instead, she submitted herself to the same rigorous assessment process DDI uses with clients—an experience she describes as both challenging and invaluable.
The assessment center tested her ability to make decisions, negotiate, coach others, and deliver executive-level presentations. She received direct feedback, learned from her mistakes, and came out stronger. It wasn’t a courtesy exercise. It was preparation.
Over nearly two decades, she progressed through various roles: research and development, global sales and consulting, and ultimately founding DDI’s Executive Development Practice and award-winning frontline leader development programs. She personally managed strategic client relationships with companies like Keurig Green Mountain, ADP, BNY Mellon, and Texas Children’s Hospital.
The Succession Nobody Expected to Work
Two years before she became CEO, DDI announced the succession plan publicly. It was a deliberate strategy drawn from DDI’s own methodology: transition leaders sooner, give them time to prepare, and make the process transparent.
During those 12 months of transition, Tacy wore two hats. One was working with her own successor to transition her current responsibilities. The other was learning everything she could about the CEO role from those who held it. The approach worked—but not without difficulty.
When she took over in 2015, she inherited the executive team. About 18 months in, she made one of the hardest decisions of her career: letting go of a long-tenured executive who wasn’t the right fit for the company’s new direction. In an organization where longevity is valued and people often retire after decades of service, this was a shock.
But Tacy had learned something crucial from DDI’s own teachings: leadership isn’t about being comfortable. It’s about doing what’s right for the organization, even when it’s personally difficult. She handled the situation with empathy, communicated the rationale clearly, and moved forward.
Strategic Transformation
Since taking the helm, Tacy has established a new strategic direction for DDI, cascading aligned initiatives and metrics to drive business transformation. She’s driven market-leading investments in technology, including virtual reality solutions for leadership development and AI-driven learning experiences. She launched DDI’s subscription model for leadership development, making personalized blended learning experiences more accessible to time-strapped leaders.
These weren’t cosmetic changes. They were fundamental shifts in how DDI delivers value in a rapidly evolving marketplace. She recognized that the next generation of leaders demands different styles of learning, and she positioned DDI to meet them where they are.
Leading Like a Girl
But perhaps Tacy’s most visible initiative has been the #LeadLikeAGirl movement. In a company where women comprise 53% of the leadership bench, she’s used DDI’s platform to advocate for gender equity in leadership globally.
Her keynote speeches on International Women’s Day, her co-authored book “Your First Leadership Job: How Catalyst Leaders Bring Out the Best in Others” (translated into six languages with over 125,000 copies sold), and her ongoing work with Fortune Magazine’s Ellen McGirt have made her a nationally recognized voice in leadership development.
But she’s not just talking about women in leadership—she’s providing actionable strategies for both women and their male allies to create measurable change. Her research shows that organizations with at least 30% women and 20% women in senior leadership are 1.4 times more likely to have sustained profitable growth.
Beyond the Office
In the Pittsburgh community, Tacy serves on the board of Pittsburgh City Theater and has maintained 25+ years of continuous fundraising service for Mount Holyoke College. DDI’s SPARK grants program, which allows employees and clients to offer hiring and leadership training to local nonprofits for free, reflects her commitment to social responsibility.
The Measure of Success
Fifteen consecutive years as a Training Industry Top 20 Leadership Training Company. Ranked #1 by Kennedy Consulting Research & Advisory. Operating in 90+ countries. Developing over one million leaders annually. These metrics tell one story.
But the real story is about a woman who could have relied on her father’s legacy but chose to earn her own. Who submitted herself to the same rigorous assessment she asks of clients. Who made difficult decisions with empathy. Who transformed a 55-year-old company while honoring its foundations.
Tacy M. Byham proved that the strongest legacies aren’t preserved in amber—they’re transformed by leaders brave enough to honor the past while building the future. That’s not just succession. That’s succession done right.
