Callum Winn

I’m Callum, a growth mentor who helps founders scale with sustainable, product-led strategies. I’ve worked across multiple startups from pre-seed to Series A, driving awareness, user acquisition, and brand growth with a hands-on, practical approach. I’ve worn many hats, had plenty of successes, and experienced failures too—which is where I’ve learned the most (and hopefully, you can too). At Whering, I led the marketing team that took us from 3,000 to 300,000 new users every month (pre-seed), achieving 98% organic acquisition and best-in-class CPI. This was powered by viral content, product-led growth, and community-driven engagement, including UGC virality and word-of-mouth. Along the way, Whering gained global recognition, being featured in Vogue, BBC, New York Post, The Drew Barrymore Show, and 100+ other publications. If you're looking to raise VC funding, being able to prove capital efficiency and scalable growth without excessive costs will give you a huge advantage-and I can help you get there. Before that, I led marketing at Gravity Co., driving a 158% increase in website traffic in just seven months. During a phase of 500% YoY growth, we achieved 80% occupancy in new buildings within the first two months. I also led crowdfunding campaigns, securing 201% of the funding goal (£500k+) from 137 investors, and worked on brand efforts that helped secure a €5.7M Series A shortly after. Beyond that, I’ve worked with startups across Education, Media, Fashion, Wellness, Direct Foreign Investment, and SaaS, primarily focusing on brand strategy and visual identity. I’ve led nationwide rebrands across 130+ retail stores and digital platforms, ensuring startups and established businesses alike build brands that stand out and scale effectively. Earlier in my career, I worked at IBM, where I developed organic social media strategies, worked on events that generated a $10M+ sales pipeline, and mentored startups as part of MassChallenge, supporting early-stage founders in tech. But mentorship isn’t just about tactics. My role is to help you think bigger, challenge your approach, and equip you with the frameworks to scale in a way that fits your business. I know what it’s like to be deep in the trenches, so my advice is always practical, tested, and tailored to your unique challenges. If you’re an early-stage founder looking for a hands-on mentor to guide, support, and strategise alongside you, let’s connect.

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  Branding

  7+ years in brand strategy & identity, leading nationwide rebrands, creative direction, and positioning to help startups build memorable, scalable brands.

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  Email marketing

  7+ years in CRM, currently managing Braze-powered email, push, and in-app messaging, lifecycle campaigns, personalised onboarding, and retention strategies.

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  Growth marketing

  At Whering, I led the marketing team that took us from 3,000 to 300,000 new users every month (pre-seed), achieving 98% organic acquisition and best-in-class CPI.

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  Apple Search

  6 years of experience

  Experienced in setting up, managing, and optimising Apple Search Ads to drive high-intent user acquisition with efficient bidding and ASO integration.