A real-estate executive who received immunity to become a witness in the federal corruption trials of both of the state’s former legislative leaders is also the top “bundler” for city Comptroller Scott Stringer.

Records show that Glenwood Management senior VP and counsel Charles Dorego rounded up $149,900 for Stringer’s 2013 campaign, more than any other supporter.

The money Dorego directed to Stringer overshadowed the $33,175 he contributed or bundled that year for all other candidates, including $9,900 for Bill de Blasio’s mayoral campaign.

Dorego didn’t return calls to explain how he became such a big Stringer fan.

The Comptroller’s Office offered no explanation, other than to say that Stringer “follows all applicable laws.”

Dorego is a key witness in the trial of former state Senate Majority Leader Dean Skelos and figured prominently in the case against former Assembly Speaker Sheldon Silver, who was convicted on Monday of extortion, money laundering and fraud.

During Silver’s trial, prosecutors showed how Glenwood went along with a scheme that allowed Silver to collect referral fees while considering legislation on a tax-abatement program crucial to Glenwood’s business.

In Skelos’ ongoing trial, Dorego testified that Skelos pushed his company to find a cushy job for his son, Adam.