The co-founder and former CEO of StreetEasy is embroiled in a bitter legal battle with McDonald’s over his alleged illegal construction of a luxury penthouse on a Manhattan condo building – rooftop space the fast food giant allegedly owns.

Michael A. Smith, who sold the popular real estate brokerage site to Zillow for $50 million in 2013, owns the penthouse apartment at 147 Reade Street in Tribeca — which includes four outdoor terraces and a swimming pool, according to the filing just before Thanksgiving McDonald’s lawsuit

It was expanded in 2007 and totals approximately 3,700 square feet on a five-story condominium project called Tribeca, built in 1987 and comprising 149 Reade Street, 165 Chambers Street and 303-307 Greenwich Street.

McDonald’s says it purchased four commercial units in 1990 and negotiated several easements – one of which allowed the company to install a cooling tower on the roofs of 147 and 149 Reade, according to court documents first reported by Bloomberg News.

According to the company, it used the space until 2006 and then replaced the cooling tower with a new system that did not take up roof space.

The next year, Smith received approval from the board to expand the penthouse unit, which resulted in the demolition of the portion of the easement to which McDonald’s claimed rights.

McDonald’s wants the roof restored to its original condition and is seeking at least $10 million in damages, according to court documents.

In 2012, McDonald’s said it had experienced “serious HVAC problems” and that a water tower and condensers needed to be installed. The company said it never gave up its rights to the rooftop space.

Years of back and forth between McDonald’s and the condo board followed. The board, of which Smith was president at the time, rejected McDonald’s request to have its HVAC unit installed in the condo’s courtyard.

In 2021, McDonald’s notified the board that it was exercising its original easement, the lawsuit says.

But a consulting engineer told the company that the roof space was “no longer available” because a penthouse had been built on it.

Smith has maintained that the board properly approved the renovation plan in 2007 and that the work was fully completed and visible in 2010.

His attorney, Emily Reisbaum, referred Bloomberg to a 2021 motion to dismiss in which Smith says the statute of limitations has expired.

The Post has reached out to Reisbaum and McDonald’s for comment.

Smith co-founded StreetEasy in 2006 with Sebastian Delmont, Doug Chertok and Nataly Kogan.

After his exit in 2013, he held various leadership positions at a number of technology companies.

According to Bloomberg News, Smith’s penthouse has already been the subject of disputes.

In 2021, the condo board alleged that Smith abused his position as president to mislead fellow owners about the expansion. The board, which claimed Smith concealed the true extent of the penthouse expansion, is seeking at least $5 million in damages.