Actor/activist Mark Ruffalo (“Spotlight,” “The Avengers”) has been house-hunting on the Upper West Side.

The actor, married to Sunrise Coigney and father of three who recently advocated for the ban on fracking in New York, recently toured a sprawling, six-bedroom Upper West Side townhouse at 161 W. 91st St.

The gut-renovated five-story brownstone, asking $9.99 million, is 6,900 square feet, and it comes with 1,600 square feet of exterior space, including a private garden and roof deck.

Details include high ceilings, a 1,200-square-foot master bedroom level, and an eat-in chef’s kitchen that opens to the garden via “a wall of glass” with a bifold door, according to the listing.

The home also boasts 12-foot ceilings and new elements like an elevator, wide-plank oak floors, and a new fifth floor that reportedly makes it the tallest townhouse on the block.

The listing brokers are Ariel Tavivian, Yair Tavivian, Francis Russo and Noam Gottlieb of Douglas Elliman.