On 25 February 2006 Greis won the men's 15 km event and became the first person to capture three gold medals at the Turin Olympic Games.

(Koreans Jin Sun-Yu and Ahn Hyun Soo became the second and third later on the same day with victories in short track speed skating.)

In the 2007/08 World Cup season Greis managed onto the podium on a regular basis, attaining three victories, three 2nd places as well as three 3rds.

After the first round of the 2012–13 World Cup, Greis announced his retirement on 5 December 2012 citing a lack of motivation, making the 20 km in Östersund on 28 November his last competition as he had dropped the sprint and pursuit.

[3][4] After two years in this post, in April 2018 he was announced as head coach of the United States men's biathlon team.