When he just missed the cut to become a state trooper, Sheehan set his eyes to the Secret Service. While he had the intention of becoming a firearms instructor, he was assigned to classroom instruction in 1984.
Although disappointed, he called the assignment a "blessing in disguise."
"Quickly after that, the position opened up for driver training and they didn't have anyone out there," he said.
From there, Sheehan traveled the country, auditing other agencies' driving programs and creating the Secret Service's program.
Drivers had previously been trained by other agencies, Sheehan said.
"If something does happen, most of us can drive, but can you drive under pressure and with control," he said.
While Sheehan's career has kept him around cars for much of his life, he isn't a self-proclaimed car fanatic. He drives a Chevrolet Suburban and his wife has a Nissan Altima.
"You can open my garage and you'll find golf clubs and hockey sticks," he said with a laugh.
But, the beauty of being in his position with the Secret Service, he had access to any car.
"I was like a kid in a candy store," he said.
While Street Smarts has done no advertising since its inception, Sheehan credits the growth in part to partnerships with the schools' booster clubs. If the booster clubs advertise Street Smarts, the company in return pays a referral fee to be used for school programs.
Street Smarts has donated just under $170,000 to are high schools since its founding.
For Armando Diferdinando, a West Friendship parent of three children who attended Street Smarts, if Sheehan can drive the president, "he's good enough to drive my kids."
"Knowing that he had taught the Secret Service, made it very reassuring," he said of sending his children to Street Smarts.
Diferdinando, who was referred to Sheehan by a friend, said all of his children had a "very good experience."
"He goes the extra mile, no pun intended," he said.
Rachael Rockefeller, a 17-year-old Century High School junior, acknowledged that driving school was not something she was necessarily looking forward to but the Street Smarts program was "very interesting at times."
She said that was because it is run by law enforcement officers.
"You know what he's telling you is legit, it's real," she said.
One difference in training drivers for the Secret Service and teenagers is their attention level, Sheehan said.
In a Secret Service class, students paying attention is a given. In high school classrooms, not as much.
"You have to make it interesting for them and make sure that they understand it," Sheehan said.
Like many other people, Sheehan said his biggest pet peeve of drivers on the road is distracted driving.
"Just because you have a license, that doesn't make you a good driver anymore than having a football makes you a quarterback," he said.
Reflecting on his career, picking out some of his favorite memories is like picking a favorite song for Sheehan.
"Looking back at my career, that I had access to the president's car keys and a key to the White House, that's pretty impressive," Sheehan said.