LISBON — It won’t be his first marathon, and it won’t be his last, but Monday’s Boston Marathon will still be a unique and rewarding experience for Michael Robitaille.

The 43-year-old father of three from Lisbon started running to keep himself in shape for his job as a firefighter in both Lisbon and Yarmouth.

“I started getting old,” Robitaille joked. “It’s physical fitness. As a firefighter, that’s really important to me, so I figured it was time to start getting physically fit.”

He didn’t jump right into running marathons, but it wasn’t like he eased into it, either.

“I ran a couple, three half-marathons first,” Robitaille said. “Then I decided it was time to set a personal goal and move on to a marathon. I did, and then I said, ‘Aw, what the hell, I’ll run another one.’ I don’t know why I’m still doing it. I haven’t figured it out yet, but it’s fun.”

The annual Boston race is widely regarded in the running community as a must-run — if you can get in. Qualifying standards for the venerable race are particularly stringent, because the race is so popular. Robitaille’s qualifying standard falls in the 3-hour, 20-minute range.

“I got in there because I knew somebody who knew somebody,” Robitaille admitted. “But I’m in.”

Monday’s run will be his second competitive run at the marathon distance. His first was at the Marine Corps Marathon in Arlington, Va., last fall. His time?

“It was four hours flat,” Robitaille said. “That was pretty good, for my first one.”

“My first goal (in Boston) is just to finish,” Robitaille added. “The second goal is to finish in the top 20 percent or so. I want to try and be between four and 4:15. I am running another in October, and I want to be at 3:40 by then.”

Training in Maine can be particularly taxing, especially when you work 12-hour days. Robitaille managed to find the time, though.

“It was tougher to train over the winter months,” Robitaille said. “I work a 12-hour shift, so I’d wake up to go to work and it was dark, and I’d get out of work and it was dark. I did a lot of training on the treadmill and then was out on the roads on the weekends.”

Time, more than distance, was important.

“The toughest thing is just being out there, mentally,” Robitaille said. “When you sit there and run for four and a half hours, there are so many things that you have to watch. You have to watch dehydration; you have to watch what you eat. But being out there for so long, it’s like, ‘Geez, am i ever going to finish?'”

Of course, training for a marathon, Robitaille isn’t running a marathon distance every time out.

“Probably four times a week, I’ll go out for between a half hour and an hour,” Robitaille said. “Every other week, I’ll go out for a two- to two-and-a-half hour run, depending on my schedule.”

The long-term benefits of running were a driving force in Robitaille’s taking to the sport, but it’s something he’s always done — in one for or another. In the 1980s, he ran track at Lisbon High School for coach Dean Hall.

Hall, still the high school track coach, might see a second generation Robitaille next season, too. Robitaille’s son, an eighth-grader, will run a half-marathon with his father this spring.

“We’re going down to Virginia to do the Marine Corps half marathon,” Robitaille said. “The only reason I’m going is for him. He really enjoys it. He’ll run eight or nine miles with me now.”

He won’t have any company in Monday’s race, though.

“There’s one guy (another firefighter) going down to the Red Sox game that day, and if I know him, he’ll probably make his way to the finish line afterwards,” Robitaille said.

Either way, he said, it’s Boston, and he’s going to savor every minute of the experience.

“Especially the finish,” Robitaille said.