He represented Ukraine at the 2004 Summer Olympics and holds multiple Ukrainian records in athletics.

From an early age he had played football and handball, but eventually focused solely on athletics.

A member of an Italian athletic club, he has been trained by Georgiy Mironiouk since 1992, and has five times been the champion of his country, including a bronze medal in 2003 at the World Championships (Paris/Saint-Denis) and silver in the 1500 m at the 2004 IAAF World Indoor Championships in Budapest.

He started the next year by winning the World Indoor Championships in Moscow, comfortably ahead of two Kenyan runners, completing 1500 m in 3:42.08.

In August 2006, Heshko won the silver medal at the 2006 European Championships in Athletics in Gothenburg.