After graduating from Dartmouth, True joined the Oregon Track Club for his first year as a professional runner. While at OTC, he was Top Mainer at the Beach to Beacon 10K in 2009, finishing 10th overall, and represented the Ivy League Alumni Select team at the Izumo Ekiden in Izumo City, Japan.
2010
In the summer of 2010, True returned to Hanover, New Hampshire, to train with In the Arena Track Club, an NGO that provides opportunities for elite athletes to compete professionally while working part-time to strengthen their local communities.[8] True coaches and manages a cross-country and track team at Indian River Middle School in Enfield, New Hampshire.
2011
True joined the Saucony Elite Racing team in 2011. Since joining Saucony, True has improved his track PR's to 7:36:59 for 3000m, 13:02.74 for 5000m, and 27:41.17 for 10,000m.[9] On the roads, he has won four national championships ranging from 5k to 15k, as well as the 2011 United States Road Circuit Championship.
True was also the top American at both the 2011[10] and 2013[11]IAAF World Cross Country Championships, finishing 35th and 6th. His 2013 performance was the highest finish for an American since 1995 and led the American team to a second-place finish behind Ethiopia, defeating Kenya for the first time since 1984.
2013
At the 2013 USA Outdoor Track and Field Championships, True finished 4th in both the 5000m and the 10000m. A top-three finish in either event would have qualified him for the 2013 World Championships in Moscow.[12]
During the Payton Jordan Invitational track meet in the spring, True ran a world-leading 13:02.74 in the 5000m, winning the race and clocking the 9th fastest time ever run by an American over that distance.[13] True also won the 2014 Manchester Road Race on Thanksgiving Day, outperforming Sam Chelanga during the last half-mile.
In spring 2016, True was coached by Tim Broe.[20] May 28, 2016, True placed 11th at the Eugene Diamond League 5000 meters in 13:12.67 in preparation for US Olympic Track and Field Trials in July 2016.[21] He placed fifth in the 5000 m at the Olympic trials with a time of 13:36.40.[22]
On June 17, True placed third in 1500 meters at 2016 adidas BOOST Boston Games in US leading time 3:36.05 behind Nick Willis and Collins Cheboi.[23]
On August 6, True placed first in the 19th TD Beach To Beacon 10K in Cape Elizabeth, Maine, with a time of 28:17. True became the first American and native Maine runner to win the race.[24][25]
On November 24, True won the 2016 Manchester Road Race, beating out one of the most competitive fields the race has seen. Both True and Leonard Korir were given the same finishing time (21:31), though the win was given to True.[26]
2017
In 2017, True coached himself and trained in Hanover.[27] On April 15, True placed 1st in the B.A.A. 5K in a time of 13:20, breaking his own American 5 km road record.[28]
On April 14, True placed 2nd in the B.A.A. 5K with a time of 13:42. It was a very close finish as Ethiopia's Hagos Gebrhiwet (1st) and American Tommy Curtin were recorded in the same time.[35]
On May 25, True placed 8th in the 2 Mile at the Prefontaine Classic with a time of 8:23.76. He went through 3000 meters in 7:52.36.[36]
On August 31, True placed 10th in the Diamond League final 5000 meters, running a near personal best of 13:04.11. American Paul Chelimo went on to break the elusive 13 minute barrier in the same race, placing 6th in 12:57.55.[38]
2019
On April 13, True placed 2nd in the B.A.A. 5K in a time of 13:44.[39]
On February 20, True ran a 10,000m PR of 27:14.95 at the TEN, a meet held by Sound Running in Southern California. The time was 27 seconds faster than his previous best. He finished 4th to Bowerman teammates Marc Scott, Grant Fisher, and Woody Kincaid and is now the 8th fastest American of all time at the distance. Recent Harvard graduate Kieran Tuntivate finished 5th in 27:17 in the historically fast race. It was his first race since September 2019.
On September 6, True won the USATF 20 km Championships in a time of 59:53.[40] The event was held in New Haven, Connecticut.
On September 11, the Strava club Tour de Woodstock[41] held their first weekly public group run. The club was formed by True, along with his current training partners Dan Curts and Fred Huxham.
In November, True announced he had agreed to a deal with Asics that will run through at least 2023.[42]
On November 7, True took home 7th place at the 2021 New York City Marathon, in a time of 2:12:53. It was his first time competing at the Marathon distance. True was the second American finisher, behind Elkanah Kibet and finished just four seconds ahead of fellow AmericanNathan Martin.
2023
On April 17, 2023, True finished an impressive 23rd place at the Boston Marathon with a time of 2:16:06.