Tune competed in the marathon at the 2005 World Championships. At the 2006 World Road Running Championships she finished fourth in the individual competition. This was good enough to help Ethiopia win a silver medal in the team competition.
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.
- 3000 metres - 9:02.08 min (2003)
- 5000 metres - 15:47.83 min (2003)
- Half marathon - 1:07:18 hrs (2009)
- Marathon - 2:23:44 hrs (2010)
- Hour run - 18.517 km (2008) WR
|2005||World Championships||Helsinki, Finland||37th||Marathon||2:39:13|
|2006||World Road Running Championships||Debrecen, Hungary||4th||20 km||1:05:16|
|2007||World Championships||Osaka, Japan||—||Marathon||DNF|
|2008||Boston Marathon||Boston, United States||1st||Marathon||2:25:25|
|Olympic Games||Beijing, PR China||15th||Marathon||2:31:16|
|2009||World Championships||Berlin, Germany||23rd||Marathon||2:32:42|
|2011||World Championships||Daegu, South Korea||—||Marathon||DSQ|
- According to the Boston Athletic Association website
- IAAF, June 12, 2008: Robles 12.87 World Record in Ostrava! - IAAF World Athletics Tou
- IAAF, February 20, 2009: Makau produces second fastest time ever, Tune clocks national record at RAK Half Marathon - updated
- Desisa and Tune take Ottawa 10Km titles. IAAF (2010-05-30). Retrieved on 2010-06-01.
- Kuehls, Dave (2010-08-01). Merga and Amare Triumph - Bogota International Half Marathon report. IAAF. Retrieved on 2010-08-02.
- Edwards, Andy (2010-10-31). Fast Kenyan double in Frankfurt; 2:04:57 and 2:23:25. IAAF. Retrieved on 2010-10-31.
- Negash, Elshadai (2011-02-13). Fast 41.54 for Merga in Bahir Dar. IAAF. Retrieved on 2011-02-15.
- Hutchings, Tim (2011-02-18). Keitany smashes Half Marathon World record in Ras Al Khaimah - UPDATED. IAAF. Retrieved on 2011-02-18.
- Clavelo Robinson, Javier (2011-02-28). Kitwara regains title, Ejigu notches victorious 10km debut in San Juan. IAAF. Retrieved on 2011-03-01.
- Krishnan, Ram. Murali (2011-06-05). Limo and Tune prevail in Bangalore 10Km. IAAF. Retrieved on 2011-06-05.