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.

Arnold Henry Conrad, architect, was born on 6 January 1887 at Clifton Hill, Melbourne. In 192 he joined the Brisbane firm, H. W. Atkinson & C. McLay. When Atkinson died in 1938, T. B. F. Gargett entered the partnership. He died on 13 February 1979 at Auchenflower, and was survived by his wife, son and daughter.

Thomas Brenan 'Bren' Femister Gargett, was born on 2 May 1898 in Brisbane. He began his career as an apprentice with H.W. Atkinson & Chas. McLay in 1914 and later became a partner in the reformed practice of A.H. Conrad & T.B.F. Gargett. Bren earned one of the first diplomas of architecture from Brisbane Central Technical College (now the Queensland University of Technology) in 1923 and went on to design several significant religious, civic, and educational buildings. Among his most valued works were the memorial library and studio at Somerville House Girls' School. During World War Two, he managed a civilian drafting office for the U.S. Army Corps of Engineers, which helped forge postwar connections and boost the firm's profile. A traditionalist in both design and method, Bren was known for his meticulous approach and insistence on reliable architecture principles. Under his leadership, Conrad Gargett became one of Brisbane's largest architectural firms, responsible for major commissions including banks, hospitals, and heritage conservation projects. He held several leadership roles within the Royal Australian Institute of Architects, including national president, and was made a Life Fellow in 1970. Bren died on 10 September 1975 in Brisbane. He had been married to Lorna Gertrude Robertson (1900-1969) since 1926.

Brisbane-based architect, foundation student at Brisbane Central Technical College and employee of the Queensland Government from 1882 to 1890. From 1890 he worked as an architect, forming the partnership H.W. Atkinson and Chas. McLay in 1907. Later partnerships were Atkinson and Conrad (1918-1927), Atkinson, Powell and Conrad (1927-1931), and Atkinson and Conrad (1931-1937). He retired from practice in 1937.

Architect Charles McLay was born near Stirling, Scotland in 1860. After training as an architect in his home country, he moved to Australia, arriving in Brisbane in 1885 where he was initially employed as a Draftsman by the Queensland Government. He worked as a lecturer and examiner at Brisbane Central Technical College between 1895 and 1901 and held various positions in professional associations in Queensland from 1900. In 1907, he entered into a partnership with H.W. Atkinson, a practice which was a forerunner of Conrad and Gargett. McLay remained a partner in the practice until his death in 1918.

William (Bill) Arnold Henry Conrad was born on 13 April 1930 in New Farm, Brisbane. His father, prominent architect Arnold Henry Conrad (1887-1979), designed the Hamilton home in which Bill grew up. Bill trained as a pilot and earned his RAAF 'Wings' in 1952 while serving with No. 23 Squadron of the Citizen Air Force. After completing an architecture degree at the University of Queensland, he joined his father's firm—then known as AH Conrad & TBF Gargett—in 1956. His father's business partner was Thomas Brenan Femister Gargett. Bill became a director in 1965. Following the retirement of his father and the death of Brenan Gargett in the mid-1970s, Bill and Peter Gargett assumed leadership of the firm. Under Bill's direction, the practice helped shape Brisbane's skyline through a range of commercial high-rise projects from the 1960s to 1980s. A key focus of his work was hospital design. Major health projects carried out during his tenure included Royal Brisbane Hospital Block 7 and Gold Coast Hospital Tower Block projects during the 1970s. Bill retired from practice in 1994. He was married to Janet Conrad (1937-2021), who worked alongside him at Conrad Gargett as a landscape architect for many years. Bill died on 11 July 2024.

Peter Robertson Gargett was born on 10 October 1932 in Brisbane. His father was the prominent architect Thomas Brenan (Bren) Femister Gargett. After graduating with a degree in architecture from the University of Queensland, Peter joined his father's firm—then known as AH Conrad & TBF Gargett—in 1957. Influenced by his father and guided early in his career by Lou Hailey, Peter made significant contributions to Queensland's architectural landscape. His work included key projects such as the Commonwealth Bank Building at King George Square, the SGIO Building (now Suncorp Plaza), and the conservation of Parliament House. Following his father's death in 1975, Peter helped lead the firm alongside Bill Conrad and others, eventually becoming chairman and managing director. He served as national president of the Royal Australian Institute of Architects from 1996 to 1997 and was made a Life Fellow in recognition of his contributions to the profession. Peter retired in 1998 and died on 19 May 2014. He was married to Christine (Chris) Jennings from 1965.