Joseph Harrison was of Scottish decent, he was the son of Thomas Harrison who died at Gadlys Ucha, 17th September 1848 in his hundredth year. Thomas Harrison joined the Independents as a member with his son Joseph.
It said that he had a vision, to build a chapel at Heolfelin. Helped to carry stones from Hirwaun Common to build Ebenezer Welsh Independent Chapel, Trecynon, Aberdare. It commenced to preach in 1812.
Rev. David Jones ordained Joseph at Ebenezer on the 26th June 1817. He played a prominent part in building of Ebenezer in 1829; such was his enormous drive and effort that the chapel was known for many years as “Harrison’s Chapel.”
In 1828 he baptised 86 infants and between 1817 and 1828 more than 1600 were baptised by him.
He also helped to build and oversaw the chapel at Nebo, Hirwaun, where he was minister from 1823 to 1835.
In 1835 there was a meeting held at 6 a.m. It was for the difference on question of baptism. He believed he could baptised through immersion if members desired it. It caused a split in the chapel so he left with 20 members who then met in houses.
Rev. Joseph Harrison was on a very small salary at Ebenezer, 10/-, 20/-, 30/- per month.
Then in 1836 they met in the Long Room upstairs in the White Lion public house. The worshippers had to walk through the bar to reach the Long Room and this was frowned upon by the chapel founders who objected to drink. In 1836 they built a wooden hut known locally as “Ty Planca” (House of Planks). This became too small so they to build Salem (Welsh Congregational) chapel at Robertstown, Aberdare across the river from “Ty Planca.” The founders carried huge stones from the River Cynon to build the chapel after their normal day’s work, in their spare time. They built Salem in 1841 at a cost of £550, on land leased from Dr. James Lewis Roberts on a site called Gadlys Uchaf Farm. Rev Joseph Harrison preached there until his death in 1851.
On the 20th October 1825, Rev. Joseph Harrison took part and preached at the ordination of Rev. John Hughes, Maendy, Glamorgan. He preached with many others at the opening of the Congregational chapel at Aber near Talybont on the 30th and May 1st 1839.
He also was also the minister of Tabernacle Welsh Independent Chapel, Brecon Road, Hirwaun. It opened on the 8th and 9th of May 1839, the cause commenced nearly a year before. He wrote a report it in “Y Diwygiwr” in 1839. He also assisted in the re-opening of Bethania, Dowlais in 22 & 23 August 1827 and at the opening of Addoldy, Llanelli, Brecon on 6 & 7 November 1828.