The purchase of Towneley was completed in November 1901 and the first exhibition opened in May 1903. The museum was directed by a sub_committee of Burnley Council and the minutes together with exhibition catalogues have been preserved in the museum archive and provide much information about the early years of of the museum. The post of honorary secretary of the sub-committee was a most important one and between 1903 and 1947 was held by three men who helped to make significant contributions to the development of the permanent collections.
Cornelius Foden was the first honorary secretary between 1903 and 1918. The museum initially only took up the South wing but, with the help of the Victoria and Albert Museum, the chapel was opened in 1905 and further expansion into the North wing continued with the art gallery opened in 1908, the Burnley Room in 1911 and the Taylor Room in 1913.
Frank Walmsley was the second honorary secretary between 1919 and 1933. The most important event during this period was the start of the Edward Stocks Massey Bequest in 1921. Most of the objects purchased for the museum in the 20th Century were paid for with money from the Massey bequest. The expansion of rooms in the North wing, held up by the war, continued first in 1920 with the kitchen, the Edward Stocks Massey Gallery built on the top floor in 1923 and the opening up of the rest of the rooms on the ground floor to display the Booth Collection in 1925 at which point the annual visitor numbers were over 233,000.
The early inventories of the permanent collections were little more than cut and paste versions of the exhibition catalogues and it not until1932 that two purposely designed registers were purchased to recording exhibits received for permanent collection and for recording exhibits received on loan or lent. By the 1930s, the layout of the museum display rooms had been well established.
Wilfred Dean was the third honorary secretary between 1933 and 1947. John Mackay, who had been head caretaker at Towneley since 1903, retired in 1931 and was replaced by William Tomlinson. His diaries from 1931 to 1951 provide a very detailed account of all aspects of preservation of the collections and the interactions with visitors. In 1944 he was appointed Towneley’s first curator and the role of honorary secretary ended with Dean.
The main events between 1951 and 1971 where the opening of the Towneley Room in 1955, the start of the Towneley Hall Society in 1965 and the restoration of the Brew House, which was converted into a Museum of Local Crafts and Industries in 1971. A start was made on a new accession register together with unique object numbers in 1955 but this still incomplete in 1971, however the first general valuation of the permanent collections was made in 1969.
In 1971, a new professional curatorial staff were appointed with the sub-committee's role being purely one of governance, agreeing a collections development policy written by the curator. Day books and index cards were introduced and the backlog of entries to the accession registers was addressed. In 1974, with local government changes the sub_commitee was replaced by Burnley Borough Council's Recreation and Leisure Committee. The accreditation system was first set up by the Museums & Galleries Commission in 1988 and Towneley was granted full registered status in 1989.
After 2000 the museum’s documentation system relied less on paper but the object entry process still used object entry forms. A start was made after 2002 to move the accession register to a collection management system. By 2016 most objects in the museum's fine and decorative arts collections had been digitally photographed and added to the CMS.
With the opening of the new wing in 2002, there was an opportunity to refresh how the collections were displayed and interpreted. Another opportunity to make the fine art collection better known came with the work of the Public Collections Foundation in 2011.