"Pretty much all of my memories are of us doing stuff outside, whether it was sports," said Sean, "or pretending to be ninja turtles in the backyard."
Rory, retired Air Force, moved his family several times, before settling down in Tabernacle, N.J., after transferring to the Air National Guard. It was there where Sean was enrolled in his third first-grade class.
"Three first-grades in one year," he said, smiling. "That was my normal."
Adapting to change, it seems, came natural for the first baseman-turned-closer.
They had spent Sean's birthday that year in a hotel in Needles, Calif., part of a two-week excursion across the country -- with three kids under the age of 6 -- following their move from Atwater, Calif., where Rory had been stationed at Castle Air Force Base.
Cary Young, brother of former A's hurler and current pitching coach Curt Young, was stationed there, too. Curt would leave tickets at the base, though the Doolittle family was already invested in Oakland season tickets.
Long before pitching there, Sean frequented the Coliseum -- less than a two-hour drive from their temporary home.
Rory, raised in the Baltimore area, tried to raise his boys as Orioles and Redskins fans, but he couldn't be surprised by their taking to the A's and, ultimately, the Phillies, following their move to South Jersey.
Sean recalls throwing a temper tantrum at the Coliseum when his dad had them leave a game early because the A's were running up the score on the Orioles.
Mostly, though, Sean learned to keep his emotions in check when dealing with his father.
"Most of the time," he said, "I'd try to shut my mouth.
"Things were very strict. We always had to get homework done before practice. If it wasn't done, I couldn't go. In high school, if I had to be home by 10:30 and I got home at 10:31, I was grounded. It sucked, but I think for my development as a person, it played a key part."
An allotted time was meant for TV and video games. But no matter the time of day, the Doolittle brothers knew they were always allowed outside.
Rory, navigating through a typical weekday work schedule, outside of a handful of tours to the Middle East lasting three to six months, was around to coach his boys essentially every year leading up to high school.
"If we weren't watching or playing baseball," said Sean, laughing, "we were watching John Wayne movies. Those were his favorite.
"He was really good at incorporating life lessons into baseball. You never cut corners, you always leave things better than the way you found them, things like that."
Like when the boys would trek down to the local baseball complex and help Rory, head of the town's Athletic Association, clean up the playing fields.
"He would drag us up there, and we would go and rake the leaves, mow the grass, tidy up the field," said Sean, "and only then could we hit. We'd be cleaning out the batting cages. There were always sticks and leaves tangled in nets and fences, and then we'd hit."
Rory's longest tour came shortly after Sept. 11, when Sean was in high school. He's now teaching ROTC classes in New Jersey, but Sean's stepmother, April, remains active duty Air National Guard and is stationed at McGuire Air Force Base.
"I'm always very proud to say he was in the International Guard, that when he was on deployment, it was something I was proud that what he was doing stood for something," he said. "At the same time, he was still dad."