PT Yejun Tak
About

Lead product designer. T‑Mobile, Microsoft, Home Depot.

I'm a Senior UX/Product Designer who works best when the problem is genuinely hard: AI systems, messy workflows, ambiguous briefs, multi-stakeholder systems where nobody agrees yet on what success looks like.

01Background

Where my product perspective comes from.

My hospitality background shaped how I think about service friction. Front-line teams don't experience products as abstract journeys. They experience interruptions, unclear policies, handoffs, urgency, and operational pressure.

That perspective carries into my product work. I design for the people who have to make decisions in real time, explain what happened, and keep work moving when systems are imperfect.

In enterprise, AI, and data products, visual polish matters. Clarity of responsibility, recovery, evidence, and adoption matter more.

02Career arc

Twelve years across enterprise, healthcare, and consumer.

Apr 2025 – Dec 2025
T-Mobile Lead Product Designer, Network & AI

Led end-to-end UX design of customer booking and service scheduling workflows tied to retail support and service operations, calendar-driven interaction flows, booking states, and enterprise design system components.

Feb 2025 – Apr 2025
Home Depot Sole Product Designer, Core AI

Designed multi-step workflow interactions and AI-assisted analytics interfaces for enterprise data teams, reducing manual reporting time by 50%.

Oct 2022 – Apr 2024
Microsoft Product/UX Designer III, Microsoft Graph Toolkit

Designed reusable Teams-aligned UI components, scalable Figma design system architecture, and developer-facing UX patterns across the Microsoft 365 ecosystem.

2022 – 2023
Anywhere Real Estate (prev. Realogy) Senior UX Designer

Designed progressive web and mobile applications, led user research and moderated testing sessions, and contributed to internal design system development.

2019 – 2022
Vita (Onlife) UX Lead, Healthcare

Led UX design of Syncs, a healthcare mobile application. Built a comprehensive design system based on Material Design and collaborated with development teams on data-driven, user-centered experiences.

May 2019 – 2022
Netflix Animation Visual Designer

Designed motion and animation for Kulipari: An Army of Frogs (Netflix animated series), including animation production, title sequences, and pitch deck design. Built interactive content in Rive and redesigned the Kulipari franchise website with immersive animated experiences.

Sep 2019 – Apr 2020
Streets Market Senior UX Designer, Retail & E-commerce

Rebranded e-commerce platform and meal kit service, integrated digital and physical retail experiences, and developed membership loyalty programs bridging online and in-store channels.

2016 – 2019
AGMD, Korea UX/UI Lead, Creative Agency

Managed and delivered 30+ client projects for brands including Samsung, Innisfree, and MVNO (acquired by Toss), achieving an average 40% increase in user interaction rates across redesigned e-commerce platforms.

2018
Oculus / Meta Oculus Launchpad Participant

Selected for the competitive Oculus Launchpad program, a VR/AR creator initiative supporting diverse developers and designers building immersive experiences.

03Perspective

How I think about design.

Operational clarity over visual polish

On the T-Mobile dashboard, three roles (fleet manager, analyst, executive) were sharing one view that served none of them. I split it into role-based defaults with context-preserving role switches. Fleet managers got their action queue at 9 AM. Executives got the weekly view they previously asked analysts to build manually. Time-to-insight for fleet managers dropped 54%. Executive sessions per week rose 38%.

Human control in AI, not against it

Designing T-Mobile's service-coordination voice AI, the temptation was to maximize automation. Instead I defined explicit capability boundaries: what the AI handles, what it routes to a human, and how the handoff carries context forward. The 12% escalation rate isn't a failure of the AI. It's the system correctly identifying its own limits. Trust comes from honesty about what AI can and can't do.

Speed is a design skill

At Home Depot I used AI-assisted prototyping to move from concept to testable interface in days, not weeks. The team could react to something real instead of debating a deck. Getting to a prototype fast isn't a shortcut. It's how you find the real problem before over-investing in the wrong answer.

Practice and research are the same problem

My HCI research asks which oversight timing regime best supports accurate human intervention when computer-use agents change workflow state across multiple steps. That's the same question I'm answering when I design Magic Apron's mid-project checkpoints or T-Mobile's AI escalation paths. Research grounded in practice produces better experiments. Practice informed by research produces better designs.

04Organizational impact

Beyond shipped pixels.

At Home Depot, I used AI-assisted prototyping to move from initial concept to testable interface in under a week. The product and data engineering team had something concrete to react to before any significant engineering effort was committed.

I ran cross-functional alignment workshops connecting AI product, operations, legal, and engineering stakeholders on the voice agent's behavior model before any wireframes existed. That protected T-Mobile's project from late-stage policy redesigns.

At T-Mobile I established a design governance model for the Quantum Design System. Product designers and engineers got self-service guidance for the most common enterprise component decisions. Informal design-review overhead dropped across multiple product teams.

I introduced a pattern of separating 'target metrics' from 'verified outcomes' in case study framing and project documentation. Stakeholder trust improved and metric overstatement dropped across the teams I worked with.

05Capabilities

What I can take from ambiguity to ship.

  • UX research and synthesis
  • Product strategy and opportunity framing
  • UX architecture
  • Enterprise dashboard UX
  • Agentic AI and voice interaction design
  • AI-assisted prototyping (Cursor, Claude)
  • Developer tool UX
  • Design systems and governance
  • Motion design and Rive animation
  • High-fidelity prototyping
  • Accessibility and state design
  • Stakeholder alignment
06Best fit

Roles and environments where my experience maps most directly.

  • Senior UX Designer
  • AI Product Designer
  • Lead Product Designer
  • UX Architect
  • Enterprise UX / Workflow Design
  • Data Product UX
  • Agentic AI Product Design
Get in touch

Interested in senior UX, lead product design, or architecture conversations?