The Rev. John Ham arrived at Melbourne on 13 December 1842 with his wife and six children. They had travelled from Liverpool, England as intermediate passengers in the gun-room of a new, 429 ton barque named the "Dublin" which had been specifically designed as a troop ship. A shipboard romance resulted in Rev. Ham's eldest daughter, Miss Jemima Job Ham marrying the captain of the ship, Captain George B. Duniam two days later. They were married by special licence in St. James Anglican Church, Melbourne by the Reverend Adam Compton Thomson.

Rev. Ham was born about 1797 in England and married Ann Job Tonkin on 30 October 1818 in Madron Parish, Cornwall. After spending time at Crewkerne, Somersetshire he was ordained on 20 August 1824 in the Baptist Meeting House in the borough of Warwick, where, after giving an account of his religious experience and his confession of faith, the ordination prayer was offered up, attended by the laying on of hands. After spending time in Teignmouth, Devon and Bilston, Staffordshire he moved to Birmingham, Warwickshire where he was connected to the Cannon Street Baptist Meeting House and the Zion Particular Baptist Chapel in New Hall Street. The June 1841 census shows his family living in Bath Street, Birmingham. Rev. Ham suffered from asthma and this was reportedly the reason why he and his family set sail for Australia the following year, seeking a more suitable climate.

Though it was their intention to settle in Sydney, their ship called first at Port Phillip. Rev. Ham carried with him a letter of introduction to Melbourne's Congregational minister, the Rev. William Waterfield and while in Melbourne, Rev. Ham was invited to preach in the Mechanic's Institute and the Collins Street Independent Church. He was well received and the following month when the "Dublin" was due to proceed on to Sydney, New South Wales, representations were made to him to stay in Melbourne. He agreed to remain for a further month during which time he would preach regularly in the Mechanics' Institute while his wife and children stayed on the "Dublin" and proceeded on to Sydney. The following month, as he was about to set sail for Sydney on a coastal vessel, he was persuaded to stay longer in Melbourne, so his family returned from Sydney in March 1843 on the "Christina."

Rev. Ham preached each Sunday morning in the Mechanics' Institute to a congregation numbering between two and three hundred people. He was much esteemed by his congregation and on 20 July 1843 a Church was constituted and again before long they started planning to build a Chapel. A block of land on Collins Street between Swanston and Russell Streets was obtained from the government for the purpose.

When the time came to lay the foundation stone Rev. Ham was on a visit to Sydney, having temporarily exchanged pulpits with the minister of the Bathurst Street Baptist Church in that town. So it was the Rev. John Saunders of Sydney who performed the ceremony on 21 May 1845, with one of Rev. Ham's sons preparing a brass plaque for the occasion.

Besides his pastoral duties Rev. Ham was involved in a number of other activities in Melbourne including the establishment of a mission for aboriginal children located at the confluence of the Merri Creek and the Yarra River. He was also a member of the Stranger's Friends Society and was on a committee to assist the survivors of the "Cataraqui" which was shipwrecked on King Island in 1845.

In August 1847 he resigned his position as pastor of the Collins Street Baptist Church and moved to Sydney where he was formally inducted as pastor of the Bathurst Street Baptist Church on 2 January 1848. Despite his worsening asthma condition he continued in this position for several years before dying on 14 March 1852 at his residence, Burton Street, Old South Head Road, Sydney. As he lay dying he said 'God is Truth, Christ is Truth, the Holy Spirit is Truth, the Gospel is truth, and on this truth I rest.' He was buried the next day following a service conducted by the Rev. Dr. Robert Ross, an Independent Minister. His widow returned to Melbourne where some of their children had stayed, and she lived there until her death in 1870.

Controversy has arisen as to whether Rev. John Ham was Melbourne's first Baptist Minister. Prior to his arrival a number of Baptist laymen had been holding services, firstly in a tent, and then in various rooms. Amongst these early Baptists was John Joseph Mouritz who had arrived in Melbourne in 1841 after having been Pastor of the 'Rehoboth Chapel' in Pitt Street, Sydney for six months. On arrival in Melbourne he set about opening a school at his residence opposite the Albion Hotel, Bourke Street, Melbourne. Shortly afterwards he moved to a dairy farm in present day Fitzroy. Here he constructed a baptistery in his garden for the adult baptisms which had previously been performed at the beach. He also built a large room onto his house. This became known as 'Rehoboth Chapel' and remained in use by a small congregation until his death in 1868.

The point in contention arises as to whether or not Mouritz can be regarded as a Baptist Minister. In 1847 he published "The Port Phillip Almanac and Directory" in which he described Rev. John Ham as the 'Pastor of the Open Communion Baptist Church Melbourne' and himself as the 'Pastor of Particular Baptist Church, Little Brunswick Street.' Then in April 1854 in a letter to "The Banner" he states 'I find you attach the term "Rev" to my name; however, not being one of "the Clergy," but simply a New Testament pastor, chosen by my bretheren in Christ to act toward and for them in that capacity, I have no claim or no right to such an appendage to my name.'

Thomas McCombie, a newspaperman who was resident in Melbourne from the early 1840s, wrote a history of Victoria in which he chose to describe Rev. John Ham as Melbourne's 'first regularly ordained Baptist clergyman.' Furthermore, the Collins Street Baptist Church regard Rev. John Ham as their first minister.