[1][3] Eastler, a native of Farmington, Maine, started race walking at the age of nine, following in the footsteps of his father Tom, and his sister Gretchen, both of whom were competitive walkers.

He earned numerous age group records and All-American titles, before entering the United States Air Force Academy in the summer of 1995.

Upon reaching his senior year, he started training again with race walking, qualifying for the World Cup, and finishing fifth at the national championships.

Eastler stopped race walking for over a year until he was reassigned to Francis E. Warren Air Force Base in Cheyenne, Wyoming.

He also posted a huge personal best in the men's 20 km walk at the IAAF World Championships in Paris, France, by placing eighteenth, tying the highest finish ever by a U.S. walker in the event, with his time of 1:22:25.

[6] At the 2004 Summer Olympics, Eastler competed as a member of the U.S. track and field team in the men's 20 km race walk, along with his teammates Tim Seaman and John Nunn.