On April 21, 2008, Tune won the Boston Marathon with a time of 2:25:25. She was then selected to represent her country in the marathon at the 2008 Summer Olympics, and was the only Ethiopian to finish, placing 15th in a time of 2:31:16. In April 2009, Tune finished second by one second in the Boston Marathon with a time of 2:32:17. After finishing the race, she collapsed and had to be taken to the hospital. Her agent said the problem was due in part to dehydration combined with the cool weather and the fact that she trained for a shorter race.
She won the 2010 Ottawa 10K race in 32:11 in late May, becoming the first woman to finish ahead of the men's winner in the mixed gender race where the men's section begins four minutes after the women. She ran at the Bogota Half Marathon in August and finished as runner-up, some six seconds behind winner Shewarge Amare. The Frankfurt Marathon followed in November and she improve her personal best by almost a minute, running 2:23:44 for the runner-up spot behind Caroline Kilel.
She started the 2011 season with a win at the Ethiopian 15K Championships, beating Atsede Habtamu at the line. She ran at the Ras Al Khaimah Half Marathon a few days later and was the runner-up, albeit some minutes behind a world record-breaking Mary Keitany. She came close to winning the World's Best 10K race in Puerto Rico two weeks later, but was edged into second by Sentayehu Ejigu. She topped the podium at the World 10K Bangalore, pipping Merima Mohammed at the line. She ran the marathon at the 2011 World Championships in Athletics in Daegu, South Korea. Despite running the first 13 miles in the lead pack, she was disqualified after consuming a drink from an unknown person in the crowd, which is against IAAF rules.