MTA Chairman Jay Walder, in office not even six months, already seems the right man for the job. And his decision yesterday to lay off 1,100 staffers isn’t the only evidence of that.

No impartial observer could fairly argue that Walder had any choice but to issue pink slips — painful as that is for those losing their jobs. Indeed, many of the 500 station-agent and 600 administrative jobs actually were to vanish, through attrition, after the MTA sprung a $383 million hole in December.

Since then, the hole’s widened by another $378 million, thanks to a shortfall in tax revenues. Who knows when the bleeding will stop?

Albany usually responds to budget gaps with new taxes, debt or gimmicks; to his credit, Walder chose none of the above.

Instead, he’s tightening the MTA’s belt.

Smart. In doing so, he’ll not only fulfill his duty to balance his books, but also ensure permanent, recurring savings.

Walder vows that the layoffs are just the start of his “top-to-bottom” agency overhaul to contain costs. (Even more job cuts are likely on tap.)

“We will be reducing overtime, consolidating redundant functions and working with suppliers to lower costs,” he says. “We will not stop until I can say that every dollar the MTA receives is spent wisely.”

That attitude is long overdue.

Besides, if agency bosses like Walder can’t rein in costs during a deep recession and a fiscal pinch such as what New York now faces, when can they?

And don’t forget: Pre-Walder, no one (except, maybe, this page) wanted to contemplate the mismatch between revenues and costs driven by overly powerful labor unions. Last year, as many New Yorkers faced wage freezes or cuts or lost their jobs, transit workers won juicy pay and benefit hikes.

Given that the money for that has to come from somewhere, layoffs seem preferable to yet another round of economy-wrecking tax and fare hikes.

So kudos to Walder for showing some mettle. And good luck to him with his broader overhaul, which will help minimize service cuts and fare hikes.

Riders should be grateful — and back him to the hilt.