Sean Johnson is a man of mysteries.

The seven-year veteran, who spent his entire career with the Chicago Fire before being traded twice on the same day in the offseason — first to Atlanta United then to New York City FC — brings valuable goalkeeping experience to the Bronx, both in MLS and internationally for the United States.

That’s not a mystery, especially for NYCFC, which desperately has needed a solid goalkeeper.

The mysteries lie off the field, where the 27-year-old swaps his goalie gloves for a fishing rod and his bright green jersey for the keys to a fast car. He won’t tell you which he likes more, but fishing and cars have equal importance for Johnson when he leaves the pitch.

“[For me], fishing is my relaxation and getaway, to have a quiet, happy space,” said Johnson, who will start in net Saturday at Yankee Stadium against the San Jose Earthquakes (2 p.m.; YES). “But if I’m looking for a hobby that’s more exciting, that gets the blood pumping a little bit, it would be cars and racing.”

Johnson’s fishing habits stem from his childhood in Georgia, where his dad would take him out for the day on the boat at Lake Lanier. When he moved to Chicago, he brought along his rod, fishing with teammates on lakes like Busse Woods and Lake Michigan. The White Plains resident said he looks forward to fishing in New York once the weather warms up, and hopes he can catch some striped and large-mouth bass. He has spoken with teammate Ben Sweat — an avid fisherman — about getting a group of NYCFC players out on the water soon.

But what Johnson likes most about fishing is how it takes him away from everything — especially the soccer field.

“You’re always focused for 90-plus minutes, it’s intense,” Johnson said. “You’re on edge, so you kind of want to take that edge off, you want to do something that’ll kind of get you into that space where you can come down a little bit.”

But when he’s not looking to cool down, he’s either watching racing or behind the wheel of a car. As a kid, Johnson watched his uncle build cars, which started his obsession. He built his own, a Nissan 370V, which he now regrets selling. Johnson said he took pride in the car, hanging out in the garage, watching and learning from the mechanics, which allowed him to fiddle with projects on his own.

Johnson – who kept a clean sheet for Team USA in a 1-0 win against Costa Rica in the 2013 Gold Cup – enjoys watching racing like the WeatherTech SportsCar Championship. He has attended races such as Road American in Wisconsin, and once owned a red Lamborghini for a year after he won an MLS competition judging the league’s fastest driver. That competition started a business relationship with Continental Tire. Johnson served as an ambassador, traveling around the U.S. to other races.

“I soaked all those things in,” said Johnson, who now drives a 2004 Lexus IS300, which he bought off former Fire teammate Matt Lampson. “It was awesome for me because I only watched them on TV.”

When he’s finished with his soccer career, Johnson hopes he can get involved with sports-car racing, but that will have to wait. In his three games with NYCFC, the 6-foot-3 Johnson showed a calming presence that wasn’t there with Josh Saunders. It’s a big sigh of relief for everyone who watched Saunders’ blunders the past two seasons finally to have a true No. 1 goalkeeper. Though some feared Johnson would struggle playing from the back – head coach Patrick Vieira’s preferred style of play is for the goalie to initiate a series of passes rather than boot it long – Johnson is doing just fine.

“[NYCFC] has been a breath of fresh air,” said Johnson, who has allowed just two goals in three games. “I know my time’s been short, but in the short amount of time, I’ve seen a lot of positives and a lot of things to look forward to for the rest of the year.”

Johnson may continue to claim he has some kind of mystique, but one thing is for certain: NYCFC’s mystery in goal is finally over.