Onejune Chang joined the varsity swim team for Great Neck High School his 8th grade year. Captain of the squad as a senior, he set several school records, including  the 50 Free, 100 Free, 200 Free, 100 Breast, 200 Free Relay, 200 Medley Relay, and the 400 Free Relay.  He was named MVP County Champion in 08-09, was the 100 free country champ as a junior and a senior, 200 free county champ as a senior as well as 100 free all-state as a junior and senior.

When not in the pool, Chang plays the guitar, piano and jazz trumpet and should be able to indulge his snowboarding passion during the winter months at Dartmouth.

Onejune is the son of Peter and Agnes and has two sisters.