The way Jake Carlock sees it, he must overcome all the “nots’’ that make him who he is.

As once one of the longest of longshots to stay around when the final rosters are announced — and not long ago no favorite to even slip onto the practice squad — Carlock’s spring and summer with the Giants represent past and ongoing battles to prove he is more than what he appears to be.

“I think for me, it’s all about effort,’’ Carlock said after a performance Thursday night that stamped him as a youngster to watch. “I’m not the biggest. I’m not the strongest. I’m not the fastest, but I can only control how fast I can go. So, every play, I’m going to give it 100 percent.’’

Effort combined with instinct and good fortune made Carlock a breakout player in the Giants’ 31-22 preseason-opening victory over the Jets. With 4:15 remaining in the third quarter, he leaped at the line of scrimmage as Jets quarterback (and former Giants draft pick) Davis Webb uncorked a pass. Carlock then achieved a rare trifecta. He batted the ball to himself, it stuck in his hands for an interception and he instantly transformed from defender to offensive playmaker, racing 59 yards for a touchdown that was as improbable as it was incredible.

This, from an outside linebacker who converted from defensive back, from a Long Islander (Babylon) who played at Stony Brook and most recently LIU Post, from a 22-year-old who grew up a Giants fan, is what dreams are made of.

“On that play, I was just trying to get the tackle and make a play,’’ Carlock said. “I saw, I think it was Webb, drop back. I saw his eye. I saw when the ball left his hands and I just got my hands on it and tracked it in. I took off running and tried not to get caught.

“I know as a defender, once you get a pick, you never want to get hawked down from behind. So, I was running as fast as I could. After I scored and was celebrating, I couldn’t even catch my breath. It was a good time.’’

A good time was had by all wearing blue. Carlock’s teammates rejoiced on the sideline and his friends and family in the seats erupted in celebration.

The scoring romp was the highlight, but not the end, of Carlock’s impressive debut. He later dropped Luke Falk for a sack. Every undrafted free agent longs to hear the kind of praise coach Pat Shurmur heaped on Carlock afterwards.

“That was awesome, wasn’t it?” Shurmur said. “He’s a team favorite because he’s so tough. When we had all of those injuries, those little nagging injuries at the first part of training camp, he took a ton of reps — more than the law allows. He’s tough, tough as nails. The sideline exploded when he scored. It was really a great feeling. He’s a fan favorite on our team.’’

Where does Carlock go from here? He was a 225-pound safety at LIU Post — a Division II program when he was there — and now is a long-haired 238-pound outside linebacker trying to find a place in coordinator James Bettcher’s 3-4 defensive front. Lorenzo Carter, Kareem Martin, Markus Golden and rookie Oshane Ximines are all ahead of him on the depth chart. The practice squad, once seemingly out of reach, is a real possibility for a player who already has caught the attention of the head coach.

And the man who runs the defense.

“He’s a really good learner, a great kid, he’s working exceptionally hard, and he’s falling in line with all of the other rookies that are trying to figure out their process,’’ Bettcher said.

The process will continue Sunday when the Giants return to practice.

“You have to take advantage of your opportunities,’’ Carlock said. “As an undrafted free agent, you don’t get many. Once those guys went down, it was time for me to step up and try my best to make some plays, and I did.’’

Mike Dawson, in his first year as the Giants’ outside linebackers coach, called Carlock “a ball of energy, he’s a million miles an hour when he practices.’’

Carlock is not as hefty as the other outside rushers but, Dawson said, “He’s a ball of muscle … a rocked-up guy.’’

Perhaps there will be a place for him with the Giants after all.