He withdrew from consideration from the Whiteness and Weisdale seat at the inaugural Zetland County Council election in 1890, but was elected to the Tingwall seat anyway.
Arthur was educated at an academy in Montrose and returned to Lerwick upon completing his education to work for his family's firm, Hay & Co, subsequently becoming a partner in the firm. Following the death of his brother, George, he assumed management of the business as the senior partner. During his tenure at the family firm, it was one of the largest employers in Shetland & was the sole largest shipowner.
As Chamberlain of the Lordship of Zetland, he engaged with tenants on his lands. The Shetland Times paints him as being on the side of the poor, saying "Not a few of the tenants on [Lord Zetland's] estate, as well as on the estate of Hayfield will sorry at his death, for in him the poor and needy, the widow and orphan ever found a sympathetic and generous friend. This claim is dubious, since Hay had testified against crofters in the 1883 Crofters Commission.
He held a long list of public positions including Deputy Lieutenant for the County, a Commissioner of Income Tax, Honorary Sheriff-substitute, a Justice of the Peace, a Commissioner of Supply, Vice-Convener of the Zetland County Council and a member of other boards and committees.
In politics, Arthur was an ardent Liberal during the Dundas campaigns. On the introduction of the Home Rule Bill, however, he did not support Gladstone and then became a Unionist.
Lerwick Town Council
- Lerwick Town Council Election November 1876
- Lerwick Town Council Election November 1878
- Lerwick Town Council Election November 1881
- Lerwick Town Council Election November 1884
Zetland County Council
- County Council Election February 1890
- County Council Election December 1892
- County Council Election December 1895
|Tingwall County Councillors|
|Councillors||Arthur Hay (1890-1897) • Alexander Hay (1897-1901) • William Duncan (1901-1909) • Lewis Garriock (1909-1913) • Robert Inkster (1913-1919) • James Mouat (1919-1935) • Selina Garriock (1935-1938) • Westwood Hay (1938-1945) • George Ross (1945-1950) • George Spence (1950-1964) • Andrew Irvine (1964-1975)|