Yohannes has trained at the Ajax Academy, in Amsterdam, since she was a child and signed her professional contract at the age of 15. In 2023-24, her first season with the Ajax senior team, she made 20 appearances in the women's Eredivisie, scoring five goals and tallying four assists.

Ajax teenager Lily Yohannes has committed to represent the U.S. women’s national team at international level. The 17-year-old midfielder was born in Springfield, Virginia, but moved to the Netherlands with her family in 2017 and was working toward eligibility to possibly represent the country as a Dutch citizen.