Leadership Lessons with Jos van Oostrum, former Senior Sustainability Director at Mars

We sat down with Jos van Oostrum, former Senior Sustainability Director at Mars, about sustainability leadership, purpose-driven business and how companies can embed impact at the heart of growth.

Why did you choose to work in sustainability?

I didn’t make a deliberate decision at the beginning and my career naturally evolved towards sustainability as I developed and grew in my roles. From an early age, I was fascinated by the connection between people and the natural environment, a connection that has always influenced my values. Over time, sustainability became something I naturally considered in every decision, both at work and in my personal life.

What personal attributes have helped you succeed in sustainability leadership?

Humility, curiosity, and a genuine interest in people, particularly those from different cultures, have been central to my career. Showing emotion and passion helps to create authentic connections. Kindness is essential because it builds strong, positive relationships. Resilience has helped me navigate the inevitable ups and downs, while creativity has enabled me to think differently and work across boundaries effectively.

What key qualities will sustainability leaders need in 2025 and beyond?

Future sustainability leaders will need resilience to stay focused amid constant change and challenging news cycles. They must also demonstrate flexible and agile leadership, understanding when and how to integrate sustainability into wider business discussions. Perhaps most importantly, they will need to communicate in ways that resonate, using clear, relatable language and focusing on tangible outcomes rather than lofty ambitions.

How is corporate sustainability evolving?

I remain optimistic about the direction of corporate sustainability. Artificial intelligence could make the discipline more efficient by managing data and reporting, freeing professionals to focus on vision, creativity, and leadership. Flexibility in how sustainability presents itself will be vital, as will an emphasis on positive impact at any scale, not just headline-grabbing ambitions.

What advice would you give to future sustainability professionals?

Share your passion and tell your personal story. Be a strong storyteller who connects emotionally and intellectually. Understand your own strengths and weaknesses and surround yourself with people who complement them. Approach situations with humility and curiosity and listen before speaking. Build trust by engaging confidently and authentically, and always use language that aligns with societal expectations and values.

Does the shift from impact to compliance concern you?

Yes, it does. The move towards compliance risks creates fewer roles, smaller teams and more tactical work. This trend reflects broader geopolitical and economic uncertainty. However, silent leadership remains: the determination to drive meaningful change even when attention shifts elsewhere. We need to support both established companies and startups to stay ambitious and define what comes next. The sustainability profession should continue to lead, not follow.

Is there enough sustainability representation at the board level?

Representation at the board level alone doesn’t guarantee behavioural change. What matters most is having agile and creative leaders across the C-suite who understand how to embed sustainability into every discussion. Success depends on how informed and connected leadership teams are. Acting as a trusted adviser or confidant to senior executives can ensure sustainability remains central to decision-making and long-term strategy.

Whether you’re hiring top sustainability talent or considering your next career move, our team would be delighted to support you.

Hanson Search is a globally recognised, award-winning talent advisory and headhunting consultancy. Our expertise lies in building successful ventures worldwide through our recruitment, interim and executive search in communications, sustainability, public affairs and policy, digital marketing and sales.