He began preaching to an Independent congregation which met at "Maesbury House", the residence of John Roberts in Kensington, South Australia.

[4] Also in 1858 Barrow left the Register to become editor, manager and co-founder of The South Australian Advertiser, whose first issue appeared on 12 July 1858.

[1] The editing of a newspaper is a sufficiently exacting piece of work for most people, but Barrow was a man of tireless energy and contrived also to carry out the duties of a member of parliament during nearly the whole of this period.

[1][5] John Barrow was also the first Mayor of the newly created municipality of the Town of Unley, and was an active member of the South Australian Free Rifle Corps.

In mid-1873, Barrow's health declined, and though he went to the intercolonial conference at Sydney as one of the South Australian delegates in the hope that change of scene might lead to its improvement, it continued to deteriorate; he died in Adelaide on 22 August 1874 of an effusion on the brain.