[5] In Jenkins' first semesters at Northeastern, the head coach was Renny Waldron, who noticed that he would start out too fast to finish strong in many of his freshman races.

By Jenkins' junior year, Northeastern's cross country and track program went through widespread staff changes and new coaches were hired.

After graduating in June, Jenkins signed with Nike and headed to Europe, where he notched personal bests in the 3,000 meters (7:41.79) as well as in the 5,000 (13:07.33).

Two weeks later he ran a personal record over 3000 meters during the Millrose Games in New York, his time of 7:39:43 was good for 3rd place in the race that was won by Ryan Hill in 7:38:82.

On September 3, 2016, Jenkins won the Fifth Avenue Mile in a time of 3:49.5, narrowly defeating the previous year's winner, Matt Centrowitz, by 0.1 seconds.

On February 11, 2017, Jenkins won the Millrose Games Wanamaker Mile with a time of 3:53.23, he defeated Olympic bronze medalist Clayton Murphy by over a second.

On May 7, 2017, Jenkins won the Payton Jordan Invitational 1500m in 3:38.30, outdistancing top Americans such as Evan Jager, Izaic Yorks, and Brandon Kidder.

In doing so he beat out many talented domestic competitors, such as Sam Prakel, Lopez Lomong, Riley Masters, and Ryan Hill.