Stylish serenity awaits at this completely rebuilt mid-century modern Sag Harbor oasis. Fresh off a meticulous reinvention, this newly expanded 4+ bedroom, 5.5 bath retreat offers over 3,500 square feet of sophisticated design details and generous, light-filled living spaces, nestled among green specimen trees on a quiet street in coveted Sag Serene. Step inside to discover a harmonious blend of style and functionality, where every detail has been thoughtfully considered. The interior features Panaget white oak floors and Danish custom millwork throughout. The soaring chef's kitchen, equipped with Caesarstone counters and luxury-level appliances, seamlessly connects to the dining area and massive patio, making it perfect for entertaining. There is a main level junior primary suite and a powder room with Restoration Hardware vanity, as well as a sprawling lounge and game room with its convenient "pool bath" leading to the outside entertainment zone: a 20x40 heated saltwater pool with an automatic cover & a custom cedar pergola, all anchoring a large green backyard with plenty of space for recreation. Also on this level: an attached two-car garage with a MyQ automatic remote system and EV charger, plus a separate, climatized home gym. Upstairs, the primary suite stuns with vaulted ceilings, a dedicated lounge space, home office nook and a luxurious bathroom with soaking tub overlooking the grounds. There are 2 generous guest bedrooms on this level plus a large flex bonus room for spillover guests. The home has a CO for 4 bedrooms but lives like a 5 BD. The list of designer upgrades is endless: striking Mod Knobs handles & Hermés-inspired pulls, chic Schoolhouse lighting, custom-fitted walk-in closets, and window treatments from the Shade Store. There are also many forward-thinking smart home upgrades like built-in Nest and Ring systems, a smart security system, Yale remote locks, a Generac whole house generator and Solaredge solar panels on the roof. Living here is a breeze. Sag Serene is the coveted neighborhood of Sag Harbor that includes Long Beach and its stunning sunsets, plus the year-round bounty of Serene Green, the area's popular farm stand and gourmet grocer. The vibrant Sag Harbor Village center is mere minutes away, as are bustling Bridgehampton shopping & restaurants. Don't miss this opportunity to live in a turnkey, tailored designer gem in the heart of the Hamptons universe.