After starting his practice, Brooke shared an office with fellow architect Jules Henri de Sibour for seven years. Throughout his 40-year career, Brooke designed houses, schools, churches, and embassies, and worked with noted architects including Nathan C. Wyeth, Horace W. Peaslee and Edwin Lutyens. Brooke designed buildings in various styles, but is most known for his Georgian Revival works. This includes the expansion of the Duncan Phillips House, home to The Phillips Collection, and the British Ambassador's residence on Embassy Row, which he co-designed with Edwin Lutyens. Brooke served as the on-site architect since Lutyens was overseas. Brooke also designed schools in the Georgian Revival style, including the expansion of the Episcopal High School in Alexandria, Virginia, and several buildings on the campus of Virginia Episcopal School in Lynchburg, Virginia. He assisted in the Colonial Revival design of the Blanche Kelso Bruce Elementary School annex in Washington, D.C. Brooke designed several embassies and ambassadorial residences in addition to the British residence. He designed the Alanson B. Houghton House, which later served as the Iranian ambassadorial residence. Other countries who chose Brooke to design or alter their embassies include the Netherlands, New Zealand, Sweden, and the US, which selected Brook to design the American consulate in Bluefields, Nicaragua. In addition to designing new houses, Brooke assisted with renovating older homes. After Herbert and Martha Wadsworth sold their home on Dupont Circle to a group of women who began a social club, the women chose Brooke to renovate the building into the Sulgrave Club. Robert Woods Bliss and his wife Mildred hired Brooke to renovate their early 19th century home, Dumbarton Oaks, and return it to the Federal style as well as add a west wing. Brooke worked with Wyeth and Peaslee on the design and construction of the District of Columbia War Memorial, which honors the 26,000 Washington, D.C. residents that fought in World War I. Brooke, a veteran of the war, spent several years working on the project and his name is inscribed on the memorial, which is sited in West Potomac Park, just south of the National Mall. For his work on the memorial, Brooke received the Washington Board of Trade's Diplomat of Merit.
Later years
Brooke was a member of the District of Columbia Allied Architects and American Institute of Architects, serving on the latter committee. He played a large role in local legislation that required architects to register with the government. Brooke was a member of several clubs, including the Alfalfa Club, Alibi Club, Beaux Arts Society, Chevy Chase Club, Metropolitan Club, University Club, Wamsutta Club, and Yale Club. Brooke served as director of Birdsboro Steel and the Brooke Iron and Work Company. On December 24, 1960, Brooked died at his Georgetown home, 3021 N Street NW. His funeral was held at Christ Church and he was buried at Oak Hill Cemetery, both in Georgetown. His wife, Henrietta Bates Brooke who served as president of the Girl Scouts in the 1930s, died seven years later. The couple had one son, Frederick H. Brooke Jr., who was born on Christmas Day 1914. Brooke was also stepfather to Henrietta's children, Elliott B. McKee and Francis McKee O'Brien.
