Agree moved to Detroit in 1909 at the age of 12. He opened his firm in 1917 after graduating from the Detroit Y.M.C.A. Technical School.^[1] His first major commission was in 1921 to build the Whittier Hotel near the bank of the Detroit River. He later went on to design many office buildings, theaters, and ballrooms. Agree was one of the Detroit architects of the 1920s and 1930s who utilized the services of architectural sculptor Corrado Parducci.

As the architecture changed by the 1960s, so did Agree's commissions. He began designing many modern-style malls. In addition to the office in the Book Tower, Agree's firm later opened an office on McNichols Road in Detroit and then a suburban office in Bloomfield Hills.

Several Agree-designed buildings have been plundered by architectural scavengers. These include the Vanity Ballroom, where several Mayan-Deco panels were torn off, and the Grande Ballroom, which brought rock band MC5 into fame, which has sat empty since closing in 1972.

All buildings are located in Detroit, unless otherwise indicated.

• Whittier Hotel, 1921–1927
• The Sovereign Apartments (Buffalo, New York), 1923 (with Lewis and Hill Architects of Buffalo, New York)
• The Stratford Arms (Buffalo, New York), 1924 (with Lewis and Hill Architects of Buffalo, New York)
• Pilgrim and Puritan Apartment Complex, 1924
• Belcrest Apartments (previously Belcrest Hotel), 1926
• Seville Apartment Hotel, 1926
• Hollywood Theater, 1927 (with Graven & Mayger)
• Grande Ballroom, 1928
• Vanity Ballroom, 1929
• Lincoln Theatre, Lincoln Park, Michigan, 1936 (remodeling)
• Westown Theater, 1936
• Beverly Theatre, 1937
• Palmer Park Theatre, 1937
• Harpos Concert Theatre, 1939
• Royal Theatre, 1940
• Trans-Lux Krim, 1941
• Showcase Cinemas Dearborn, Dearborn, Michigan, 1941
• Duke Theatre, Oak Park, Michigan, named after Duke Ellington, 1941–1947
• Park Theatre, Lincoln Park, Michigan, 1942 (remodeling)
• Nadell Furs Building, 1944^[2]
• Woods 6 Theater, Grosse Pointe, Michigan, 1948
• Southgate Shopping Center, Southgate, Michigan, 1957
• Flint Tavern Hotel, Flint, Michigan
• Highland Lodge Apartment Building, Stamford, Connecticut
• Detroit Zoo Holden Reptile House, Royal Oak, Michigan

The Mall a.k.a The Pontiac Mall [Waterford Township, Michigan] 1962

• Jewish Community Center, West Bloomfield, Michigan
• Oakland Mall, Troy, Michigan 1968
• Panama City Mall, Panama City, Florida
• Trenton Village Theatre, Trenton, Michigan
• Wabeek Building, Birmingham, Michigan (this is credited to Agree, but all records indicate it was designed by Albert Kahn in 1928)
• Wilshire Residential Hotel

• Charles N. Agree, Buffalo As An Architectural Museum, link

• Hill, Eric J.; John Gallagher (2002). AIA Detroit: The American Institute of Architects Guide to Detroit Architecture. Wayne State University Press. ISBN 0-8143-3120-3.
• Meyer, Katherine Mattingly; Martin C.P. McElroy with Introduction by W. Hawkins Ferry & Hon A.I.A. (1980). Detroit Architecture A.I.A. Guide (Revised ed.). Wayne State University Press. ISBN 0-8143-1651-4.