In 1890 HW Atkinson founded the firm which has been known successively as: HW Atkinson (1890-1907); HW Atkinson & Chas McLay (1907-1918); HW Atkinson & AH Conrad (1918-1939); AH Conrad & TBF Gargett (1939-1965); Conrad, Gargett & Partners (1965-1972); Conrad, Gargett & Partners Pty Ltd (1972-1982); Conrad & Gargett Pty Ltd (1982-2004); and from 2004 to 2023 as Conrad Gargett. In early 2023 Conrad Gargett merged with Architectus.

The architectural work of the firm includes Trades Hall, McWhirter and Son, Craigston Apartments, the Courier Mail Building, and the Empire (later St. James) Theatre in Albert Street.

Born in Vienna on 28 July 1903. Karl Langer graduated in 1926 in Vienna as an architect from the master class of Peter Behrens. He married Gertrude Fröschel on 14 May 1932. They migrated to Australia in 1939 and settled in Brisbane in 1944. He lectured at the University of Queensland, and later also at the Queensland University of Technology. He was fellow of the Royal Australian Institute of Architects and of the Australian Planning Institute. He was also the first president of the Institute of Landscape Architecture and an executive member of the National Trust. He designed many of Queensland's best-known buildings, including the chapel at St Peter's Lutheran College in Brisbane. He died on 16 October 1969 in Brisbane.