Chelsea resident Jason Mayfield had trouble holding back his emotions Oct. 11 in downtown Chicago.

Mayfield glanced at the timing clock as he crossed the finish line in the Chicago Marathon and he realized his time of 3 hours and 3 minutes qualified him for the 123rd-annual Boston Marathon in April 2010.

“It was kind of surreal,” Mayfield said. “I was misting up with tears after I finished.”

When Mayfield signed up for his sixth marathon run, he simply expected to improve his time by a few minutes as he continued his life-long goal of attempting to qualify for the prestigious Boston Marathon.

Mayfield, 31, worried about how long it would take him to qualify for the Boston Marathon after running a time of 4 hours and 13 minutes in the Atlanta Marathon in 2007, which was Mayfield’s first marathon. He knew he needed to run a 26.2-mile marathon in under 3 hours and 10 minutes to qualify.

“I thought it would take me 30-40 years to make it,” Mayfield said. “I just kept getting faster. I was very surprised.”

Mayfield, a literature teacher at Columbiana Middle School, never imagined he would become a marathon runner as a child.

“I was the last kid to finish in soccer practice sprints,” Mayfield said. “I was always the slowest kid.”

Mayfield said he drew support in Chicago from his sister, Erin Neblett, and her husband, Phil, who are also Chelsea residents. Mayfield said the Nebletts began running marathons with him after he ran in Atlanta.

“They told me even though they would be a little behind me, they would be thinking about me at miles 20 and 21,” Mayfield said.

Mayfield said the couple, which finished the Chicago Marathon together with a time of 4 hours and 45 minutes, was instrumental in planning the trip to Chicago, as they booked the flight and made hotel reservations for the group.

“It was great having them there,” Mayfield said. “I would still be at the Birmingham airport if not for them.”

Mayfield said he is proud he can use his accomplishment as a real-life example to his students about what they can accomplish.

“As a teacher, you tell kids their dreams are possible,” Mayfield said. “(Qualifying for the Boston Marathon) was kind of cool.”