He holds the record for the longest continuous period as the world number-one-ranked men's recurve archer, from August 2011 to April 2013.

Initially, Ellison shot with a compound and represented the United States internationally as a youth archer with the bowstyle.

He switched to recurve on the recommendation of coaches at the national training center in Chula Vista, California, where he has spent much of his time.

[11] Ellison and Casey Kaufhold won the bronze medal in the mixed team event at the 2024 Summer Olympics held in Paris, France.

Ellison then earned the silver medal in the individual event, losing the final 5–6 on a tiebreaker by having his perfect 10 being a couple of millimeters away from the center than that of his opponent five-time Olympic champion Kim Woo-jin of South Korea.

Two months after the 2020 Summer Olympics, he won the silver medal in the men's team event at the 2021 World Archery Championships held in Yankton, United States.