I started in the trenches.
I was a network engineer who built data centers, configured BIND and POP3 servers, and designed cloud hosting infrastructure before "cloud" was a buzzword. I have certifications that don't matter anymore: CCNP, CCDP, CCIPTD, Network+, A+. I've written code in C++, Python, Pascal, Basic, HTML, and JavaScript.
I'm not hands-on technical anymore. I don't write production code. But I know how systems work, how they break, and how to build teams that make the right decisions. That's what matters at the CTO level.