 In 1880, he became partner of Rotch & Tilden (Boston) with George Thomas Tilden, designing churches, the Memorial Library in Bridgewater, Massachusetts, gymnasiums of Bowdoin College and Phillips Exeter Academy, various buildings of Milton Academy, the art schools and art museum of Wellesley College, and many private houses and business blocks throughout the United States.In 1893, he designed Ventfort Hall in Lenox, Massachusetts for George Hale Morgan and Sarah Morgan, the daughter of Junius Spencer Morgan.In 1884, he designed for his brother, Abbott Lawrence Rotch, the Blue Hill Meteorological Observatory, the oldest, continuously operated weather Observatory in the United States – now both an International Benchmark Climate Station and a National Historic Landmark.