A Korean-born American, Dayoung began her advertising career as a Creative Intern at Crispin Porter + Bogusky in Miami. Over the course of her 10 years at CP+B, she rose to become Creative Director and Vice President, and opened its London office. Working on brands including Coca-Cola, Nike, Microsoft and Mondelez, she garnered numerous awards, including prestigious D&AD Pencils and Cannes Lions. After her time at CP+B, Dayoung joined Mother London, leading clients such as Boots Pharmacy and Notonthehighstreet.com. In 2020, she spearheaded the agency's largest global production campaign for Dubai Tourism amidst the COVID-19 pandemic. Later, at VMLY&R, she led global accounts like New Balance and helped Wendy's UK return; her "Camden Makeover" campaign generated over 2 billion impressions and became the brand's most successful new store launch in the UK. In 2024, she made a jump to her first in-house opportunity and joined YouTube Creative Studio to lead YouTube's global reputational work, focusing on strategy, communication, innovation and design for YouTube's role in society, scaled across EMEA, the Americas, and APAC.