Don’t hold your breath expecting Dean Fuleihan, the designated First Deputy Mayor, to curb any of Mayor-elect Zohran Mamdani’s more unrestrained impulses. Fuleihan didn’t exercise such restraint during his tenure under Bill de Blasio, and it seems unlikely he’ll start now.

Compounding the situation, Mamdani’s choice for chief of staff, Elle Bisgaard-Church, is set to be a prominent voice echoing the same radical ideals that have characterized Mamdani’s political journey thus far. Her influence suggests a continuation of the progressive policies that have marked Mamdani’s career.

While an assemblyman’s missteps might go largely unnoticed, any blunders by the mayor have sweeping consequences, affecting the lives of over 8 million New Yorkers. The stakes are considerably higher, demanding a level of caution and prudence that seems in short supply.

Some may find comfort in Fuleihan’s non-disastrous past as a senior aide to then-Speaker Shelly Silver and other legislative leaders. However, his track record as budget director and first deputy under de Blasio paints a different picture, one lacking in fiscal discipline.

During Fuleihan’s four-year tenure, the city budget ballooned by 18%, rising from $72 billion to $85 billion. Notably, this period also saw several of the mayor’s most ill-advised projects spiraling into waste, all under Fuleihan’s watchful eye. His leadership did little to rein in these excesses, raising concerns about his ability to manage the city’s finances effectively in his new role.

• De Blasio city-run ferries ran a double set of books, reporting $524 million in expenses when a comptroller’s audit found $758 million; the per-ride subsidy was 50% larger than reported in Blas’ final year.

• Fuleihan also failed to impose any fiscal discipline on First Lady Chirlane McCray’s woeful ThriveNYC, which burned $850 million on mental-health programs to no evident benefit to anyone except the folks they employed.

• He also oversaw de Blasio’s bogus “Citywide Savings Initiatives” which set aside the long-established PEG rules for finding efficiencies for a host of bogus “savings” that centered on re-estimating costs rather than reforming operations — and Blas’ ridiculously overoptimistic “replace Rikers” plan, which is now taking twice as long and costing more than twice as much to build (smaller) replacement jails.

In short, Mamdani tapped a “watchdog” who was a lapdog for de Blasio and can be expected to be as bad or worse now.

He’s not so much a green-eyeshades wise man as a willfully-blinkered old fool.

Meanwhile, the true toughness will come from Bisgaard-Church, the commissar enforcing the progressive party line on everyone at City Hall.

Various would-be voices of reason are angling to get responsible types into Mamdani’s brain trust, but the new mayor plainly means to have a staff who’ll cheer his step.

In other words: It’s full speed ahead . . . until the fairy dust runs out.