Mark Brennan
AI and Engineering Leadership advisory at freelance
Based in Ireland · 20+ years experience
Summary
Technology & Engineering Leader | CTO / VP Engineering / Director | AI Operationalisation | Interim & Contract
About
I am a technology leader with 20+ years of experience building and leading engineering organisations, from early-stage startups through to large global enterprises.
I have had the chance to build a few things from the ground up. I founded the Dublin SAP AppHaus and grew it from zero to 240+ engineers. At Workhuman, I built the engineering function from 6 to 100+ people during a period of rapid growth, as the business grew from $40M to $250M in revenue. As founding CTO of ClarityCX1, I helped raise $1.6M and took a Salesforce-native SaaS product from an idea to production. Most recently at Datalex, I led engineering across a major platform modernisation and helped put AI into production in a revenue-critical airline pricing system.
Across those experiences, Ive learned that technology problems are rarely just technology problems. You can have good people and good technology and still struggle if the product, engineering organisation and business arent pulling in the same direction. A lot of my work has therefore been about getting those pieces to work together, whether thats building an organisation, changing how teams work, modernising a platform, improving delivery or helping turn a new technology into something that actually gets used.
AI is the latest example of that. Im interested in the practical side of it: where it can improve the customer experience, remove friction for teams, improve decisions or change how work gets done. Ive led AI adoption across engineering and, more recently, the delivery of AI systems into production. I think the interesting question now is not just how we add AI to existing processes, but where agentic systems can genuinely change the way a workflow operates.
I enjoy working with CEOs, boards and senior leadership teams, but Im equally comfortable getting into the detail with engineering and product teams. My background in consulting and client delivery has probably shaped that more than anything else.
Im currently open to senior technology and engineering leadership roles, as well as contract and interim engagements. Im particularly interested in situations where an experienced technology leader can help get an organisation, programme, transformation or significant technology initiative moving.
Skills
Software Architecture, Cloud & Infrastructure, Platform Modernisation, Engineering Leadership, Vendor Management, Data & AI
Regions covered
Industry experience
SaaS
At a glance
Mark brings hands-on experience across Software Architecture, Cloud & Infrastructure, Platform Modernisation, Engineering Leadership, Vendor Management, Data & AI. Available for engagements across Europe, North America. Industry experience includes SaaS.
How fractional CTO engagements with Mark work
Mark works on a fractional basis — typically one to three days a week for an agreed engagement length — so you get senior technical leadership without the cost or commitment of a full-time hire. Engagements commonly include technical due diligence, board reporting, engineering team leadership, technology strategy, architecture reviews, hiring support, and stepping in as interim CTO during a transition.