Expert Consulting Solutions for Business Growth

Let's explore what's possible with the right technology strategy.

Ismael N. (Numi) Castillo

Numi Castillo

With over two decades of experience driving digital transformation across financial services, energy, and technology sectors, I bring a unique blend of technical depth, business acumen, and execution discipline. As a former CTO, strategic consultant, and program leader, I specialize in aligning technology with enterprise goals—translating complexity into clarity, and vision into value. Whether leading Fortune 100 cloud initiatives, architecting zero-trust environments, or building go-to-market strategies, I deliver scalable, secure, and measurable outcomes. What sets me apart is my ability to navigate ambiguity, mobilize cross-functional teams, and architect technology strategies that resonate at both boardroom and engineering levels.

  • Technology decisions at enterprise scale carry $100M+ consequences. In my advisory roles and through strategic consulting engagements, I've guided C-suite executives through technology investments that fundamentally reshape their competitive position. When optimizing technology operations, my strategic analysis has delivered $10's of millions in annual savings while enabling expansion into new markets. As an IT budget stuard and through vendor strategies I have reduced operational costs by $13M+ annually while establishing the technology foundation for the digital transformation. I bring pattern recognition from 20+ years of enterprise technology leadership—identifying where organizations consistently fail.

    Let’s work together in execution providing the strategic framework to avoid those pitfalls while capturing maximum value from technology investments.

  • As a former Chief Technology Officer, I have led enterprise-wide modernization initiatives across infrastructure, cloud, cybersecurity, and software development. I’ve built high-performance technology organizations that deliver measurable outcomes—whether launching zero-trust security programs, scaling multi-cloud architectures, or embedding DevSecOps into legacy environments. My leadership style blends vision with execution: aligning cross-functional teams, shaping product portfolios, and instilling delivery accountability. I create cultures that foster innovation while managing risk, cost, and compliance at scale.

  • My architectural approach balances technical rigor with business relevance. I’ve designed complex systems across the full stack—spanning cloud-native platforms, data center strategy, and integrated enterprise solutions. Fluent in both legacy modernization and greenfield design, I bridge conceptual models with delivery realities, ensuring resilient, secure, and scalable architecture. I lead with standards and structure—developing frameworks, transition states, and reusable design patterns—while mentoring teams to adopt best practices across SDLC, compliance, and platform performance.

Most CEOs know exactly what they want their technology to accomplish.

The challenge? Bridging the gap between boardroom vision and engineering reality.

I help companies align strategic vision with proven execution, turning technology into a permanent competitive advantage—without the overhead of a full-time CTO hire.

Discover how fractional CTO leadership can accelerate your next breakthrough.

Schedule a discovery session

Engagements begin with a discovery session to assess needs and set clear objectives.

Every successful engagement starts with clarity.
This complimentary discovery session is designed to understand your organization’s current challenges, strategic priorities, and desired outcomes. Together, we’ll assess where you are today, where you need to go, and how technology can be leveraged to accelerate results.

What to expect:

  • A focused 45-minute conversation with Ismael Castillo

  • Exploration of your business goals, technology landscape, and transformation needs

  • Identification of potential focus areas for advisory, Fractional CTO, architecture, or execution support

  • Recommendations for next steps

Book a discovery session