He studied at Oklahoma State University and is a five-time Big 12 Conference champion (three times in hammer, twice in weight throw).

[5] After finishing school, he gained an athletic scholarship to study a multi-disciplinary degree at the Oklahoma State University.

[3][6] In joining the American college, he followed in the footsteps of a fellow Border Harrier, distance runner Tom Farrell, who began studying there in 2010.

[7] Miller began to compete athletically for the Oklahoma State Cowboys team and took up the weight throw event.

In July that year he had another best with a mark of 67.56 m (221 ft 7+3⁄4 in) before going on to represent Great Britain in the qualifiers at the 2012 World Junior Championships in Athletics.

He defended his Big 12 hammer title with a stadium record in Waco, Texas and won at the NCAA qualifier meet with a new best of 71.60 m (234 ft 10+3⁄4 in).

[10] He gave his worst performance of the season at the NCAA Outdoor finals, finishing in ninth place with a sub-65-metre throw.