Growth Marketer · MD × Performance × Automation · 8 yrs 10 mos
Seongjoon Park
I push ad efficiency to its limit — and grow what sits outside the ad.
I run 9 ad channels in-house for a Korean HMR (home meal replacement) brand, mostly without agencies. My background is marketplace merchandising — assortment, visibility and pricing — so when efficiency stalls I fix the product page, the category and the coupon structure, not just the bid. I built our unified performance dashboard myself with Claude Code.
- j1o2o1n7@naver.com
- +82 10-8916-5977
- Seoul, South Korea
Current role — Jul 2025 – present
- +₩1.02BMonthly revenue at the same ad spend₩3.08B → ₩4.10B on one marketplace · spend −4.7%
- +366%pBlended ROAS across 9 channels964% → 1,330% · H1 2026 vs H1 2025
- +83.8%Conversion revenueon +33.3% ad spend — 2.5× the pace of spend
- +468%pCoupang 1P (Rocket) ROAS1,426% → 1,893% · 10 straight months above the pre-hire peak
- −22.8%pBrand-keyword dependency37.9% → 15.1% · budget moved to new demand
- +36.6%Total revenuewith paid share held flat — growth from outside the ad
ROAS = conversion revenue ÷ ad spend, before VAT and marketplace fees; period figures are spend-weighted. All numbers come from the performance dashboard, as of 2026-09-09. ₩1B here means one billion Korean won (about USD 750K).
What I actually do
- PerformanceCoupang 1P / Wing / NCA, Naver Shopping Search · Power Link · GFA, Meta Collaborative Ads, Kakao, and vertical marketplaces (Kurly, B-Mart, Ezwel, Ably) — run directly, with channel-level raw data pulled and checked myself.
- Merchandising30+ marketplaces: assortment, pricing, promotions. Daily ranking-score management on Naver and Coupang, marketplace SEO, category and search-tag work, and a coupon structure that cut Coupang price-matching cost by up to 95%.
- Data & automationBuilt a unified dashboard over 9 channel reports (56 pivot tables) with Claude Code — parsing, validation and daily monitoring. Eight automations cut monitoring time by 30%+; RPA at a previous company saved 2,860 hours a year.
- LeadershipMarketing team lead twice and a sales manager. Designed the team structure and rebuilt a team from 2 people to 19. Back in a hands-on role by choice.
Career
- Own ad and visibility strategy for every marketplace outside the brand's own store — 9 channels, mostly without agencies.
- Same marketplace, July revenue ₩3.08B → ₩4.10B while spend fell 4.7%.
- Blended ROAS 964% → 1,330%; Coupang 1P 1,426% → 1,893%; Naver GFA 304% → 586%.
- Built the team's unified performance dashboard — product-level drill-down, price-matching-cost monitoring — plus eight workflow automations.
- Revenue on the marketplaces I owned grew 5,000% year over year (₩3M → ₩150M per month).
- Smart Store repurchase rate 1.8% → 11.2%, average order value +49%.
- Naver Shopping rank 63rd → 3rd; search-ad ROAS 182% → 514%.
- Opened Kurly, B-Mart and Hyundai Ezwel; built the CS, logistics and margin-guideline processes from scratch.
- Turned an operating loss of ₩890M into a profit of roughly ₩500M.
- Direct sourcing and a second factory cut the cost ratio 33.8% on average; out-of-stock SKUs −48%.
- Naver non-paid traffic +128%, Coupang consignment revenue +304%.
- Introduced RPA and scraping for review, rank, stock and competitor monitoring — 2,860 hours saved per year (1.5 FTE).
- The company's record year — revenue ₩56.65B, operating profit ₩10.4B (audited financials).
- Designed the marketing team's structure and grew it from 2 people to 19.
- Ran ₩150–200M of monthly ad spend; category-specific strategy cut spend 41% at equal revenue.
- Naver Brand Day: 10+ events, peak daily revenue ₩379M; live commerce peak audience 350,000.
- Price-comparison matching (Naver Shopping, Danawa, Enuri) for eBay Korea, 11st and Tmon listings; eBay BEST 100 review.
- Top performer of ten in the internal promotion. This is where the habit of working from product and price data started.
Tools
Ads Coupang Ads (1P / 3P / NCA) · Naver Shopping Search, Power Link, Brand Search, GFA · Meta and Meta Collaborative Ads (CPAS) · Kakao Moment · Mobion · GDN
Commerce Coupang Rocket / Wing · Naver Smart Store and Brand Store · Cafe24 · Godomall · EasyAdmin · Sabangnet · 30+ marketplace back offices
Data & automation Excel (pivot tables, dynamic arrays) · Google Sheets · GA4 · GTM · Power Automate · UiPath · Zapier · Make · Claude Code · GPT
Certifications Search Ad Marketer Level 1 (KAIT, 2022) · Google Analytics IQ (2024)
Looking for
Role Performance marketing · growth · online merchandising
Location Seoul, South Korea
Availability Currently employed — open to discussing a start date
This one-page summary is written for English-speaking readers. The full report — performance charts, project write-ups and a live demo of the dashboard I built — is in Korean at sjpark-growth.github.io.
© Seongjoon Park · 2026