The Parish of St. John dates from 1823 when the church was built as a chapel under the care of the mother Church of St Michael. The industrial revolution had seen new industries established and the population of Workington had grown quickly as people from the surrounding countryside and labourers from Ireland were employed in the town. As the population grew St.Michaels became too small and a grant of money was received from the government to build an additional church, “capable of containing 2000 persons”. The grant money for the building came from funds available to build new churches as thanksgiving for victory at the Battle of Waterloo. The land on which the new church was to be built was presented as a gift by John Christian Curwen, the site being chosen by popular vote amongst the people who would use the church. A report at the time says “It is situated in the heart of the town on a valuable piece of ground, the gift of Mr Curwen, selected by the inhabitants, as Mr Curwen gave them choice”. Another possible site was the top of Elizabeth Street and this became the site of St John's vicarage until a new vicarage was built at Thorncroft Gardens in the 1980's.
November 1821 saw the site being cleared, foundations prepared and in the stone quarries at Schoose and Hunday, quarrymen and masons were preparing the blocks of stone to be used in the building. The new church was completed in 1823 and plans for the building's dedication and consecration were made. The plaster on the walls however was not dry and after the service on 27th November the church remained closed for months before it could be used for services. At this time there was no organ, with the first organ being installed in 1826.
The church cost £10,488 (around £860,000 in today's money) to build and was designed by Philip Hardwicke, as a copy of St. Paul's, Covent Garden, London, which was designed by Inigo Jones. A local report at the time stated "There is a handsome portico of the Roman Doric Order" and the interior was described as "plain light and airy". The parish room was added in 1881 costing £580. St John's was planned as a mission chapel, its main focus being preaching and evangelism. To this end a large pulpit originally stood in front of the altar, where it housed a clerk's desk at ground floor level with a reading desk behind, with stairs which led to a tall pulpit.
In 1886, Canon Thornley took steps to restore Holy Communion to its proper place in the church service and the pulpit was removed from its place in front of the altar. In 1895 Rev. Canon Greene as vicar wrote “St.John's is neither beautiful nor adapted to public worship” The roof was put in order first but then plans were made to move the chancel to the east end of the church and rebuild the organ. After holding services in the parish rooms or the Drill Hall in Edkin Street, the changes were completed in 1904. The altar was given prominence and a new font was placed on the old chancel steps.
1914 saw the arrival of Rev. J.R Croft who consulted Mr J.N. Comper, an authority on the neo-classical style in which St. John's is built, about the church interior. Mr Comper visited in 1915 and made recommendations but World War I meant these were not followed up. Mr Comper suggested reversing the seating to the original direction, constructing a new sanctuary and replacing the gallery removed in 1904 at the east end. Some changes began in 1918 but the depression of the 1920s. and 1930s set in. In October 1930 Rev J.R.Croft reported that if the parish could raise £720 to remove pews, Mrs Yeowart would pay for the Comper Altar, sanctuary and part of the west window. The church reopened as we now see it at the end of 1931.