 John Hennessy retired in 1924, and the firm continued under Jack Hennessy Jnr, retaining the name, though they were also known as Hennessy, Hennessy & Co.In the 1920s, Queensland Archbishop Duhig commissioned a number of projects for the Catholic Church in Brisbane, including the never-built Holy Name Cathedral, Brisbane.In the 1930s Hennessy designed a series large office buildings for three different insurance firms in three countries, and has been described as Australia's first international architect.