Thomas Alexander O'Brien was born in Thames on 11 June 1888, the son of Thomas O'Brien, a local police constable, and his Scottish-born wife, Rose Ann Gray. Details of his early life are sketchy, but it appears he went to Australia at a young age. On 5 April 1913, at Sydney, he married Mary Gallagher. O'Brien probably obtained theatrical experience in silent movie houses in Australia, then returned to New Zealand in 1916 to manage three Wellington theatres for New Zealand Picture Supplies.
Formed in 1913, New Zealand Picture Supplies was an amalgamation of two rival cinema and film-distribution companies, Hayward's Picture Enterprises and John Fuller and Sons. The company imported films from Britain and the United States and distributed them throughout New Zealand. O'Brien held a variety of managerial positions including national publicity manager, film manager and eventually exhibitions manager. By 1919 he was living in Dunedin, and in the early 1920s he purchased the Empire Theatre in Stuart Street. By 1925 he was in Auckland and had become the owner of Everybody's Picture Theatre in lower Queen Street. He soon acquired a number of Auckland cinemas, including the Princess (later the Plaza) and the Rialto in Newmarket, the Theatre Royal in Kingsland, the Tivoli in Karangahape Road, the Regent (later the Lido) in Epsom, and the Britannia in Ponsonby. By the end of the decade Thomas O'Brien's cinema chain was the third largest in New Zealand.
The late 1920s was an exciting time in the cinema business. 'Talkies' were introduced and picture houses were becoming so spectacular that they were an entertainment in themselves. This phenomenon found its greatest expression in the 'atmospheric' cinema. Known as 'soft-top' theatres (in contrast to the usual 'hard-top'), they incorporated coloured lights playing on prisms which suggested 'the sky by night, with stars twinkling and fleecy clouds drifting across the face of the moon'. O'Brien brought the atmospheric cinema to New Zealand in September 1928 when he opened the New Empire Theatre in Dunedin. Built at a cost of nearly £100,000, it seated over 2,000 people. Much of the decorative inspiration had been provided by the Capitol Theatre in Sydney.
In 1929 O'Brien secured a long-term lease over the abandoned city markets site at the corner of Queen and Wellesley streets in Auckland. He persuaded a handful of wealthy and influential local businessmen to finance the construction of an atmospheric theatre which would be New Zealand's largest, seating nearly 3,500. O'Brien then convinced the Bank of New Zealand to advance a loan of £180,000. There is no evidence that he invested any money himself. O'Brien's florid imagination and the interior design by Charles Bohringer and Arnold Zimmerman produced a remarkable building, with Indian motifs, waving palm trees, and female ushers wearing voluminous pantaloons. Beneath the theatre a winter garden with a large dance floor could accommodate 1,500 people. However, the size of the loan and the escalating construction costs were debated in Parliament, and there were calls for a government inquiry into the affair; the total cost was estimated to be over £200,000.
Despite the controversy, the Civic Theatre opened with great fanfare in December 1929. Unfortunately it was built at the onset of the depression and was not a financial success. O'Brien's determination to screen British, rather than American, films also contributed to poor attendances. Falling receipts led to the collapse of O'Brien's company, and in 1930 he transferred management of the Civic to Amalgamated Theatres. He moved to Australia in 1932.
In Australia O'Brien was involved in theatre management, but his fortunes never again reached the heights of the 1920s. He died in somewhat straitened circumstances, in St Kilda, Melbourne, on 21 May 1948, survived by Mary, two sons and two daughters. A testament to O'Brien's personality and showmanship, the Civic Theatre remains one of Auckland's most distinctive and well-loved buildings.