Sidney Holland was born in Greendale in the Canterbury region of the South Island, the youngest child and fourth son of a family of eight children.

After the war, Holland and one of his brothers established the Midland Engineering Company in Christchurch, which manufactured horticultural spray pumps and operated a profit-sharing scheme with its employees.

During the Great Depression, Holland also became the President of both the Canterbury Employers' Association and the Christchurch Businessmen's Club, which brought into contact with the conservative New Zealand Legion and the short-lived Democrat Party, which opposed the Forbes–Gordon Coates United-Reform coalition Government.

[9][10] After his father Henry was incapacitated in a serious accident, the older Holland and encouraged Sidney to take his place as the Reform Party candidate for Christchurch North during the 1935 general elections.

Sidney Holland served as the Deputy Chairman of the short-lived War Cabinet, which collapsed in September 1942 after the National Party objected to Labour's handling of an unofficial miners' strike in the Waikato region that same month.

Under Holland's leadership, National repeatedly attacked the Labour Party's socialism, "big government" bureaucracy, collectivism, and the power of the trade unions.

Some important policies propagated by the National Party included individual freedom, a free market, minimum bureaucratic intervention, restriction and regulation, and an acceptance of the welfare state.

[17] During the successful 1949 general election, Holland capitalised on the threat of Communist expansion in Eastern Europe, the government's perceived unwillingness to counter the militant waterfront unions, persisting wartime restrictions, and rising inflation.

[18] The Sidney Holland National Government implemented economic reforms, dismantling many state controls including butter and petrol rationing.

To solve the partisan-infected issue Holland called for a referendum to be held on the same day as the general election of 1957, but the proposal failed to make the ballot.

[22] In 1951, Prime Minister Sidney Holland faced a major challenge from the militant Waterside Workers' Union during the 1951 waterfront dispute (13 February – 11 July 1951).

The 1951 waterfront dispute was sparked by the refusal of shipowners to give a 15 per cent wage rise to the watersiders who proceeded to ban overtime work.

When the watersiders refused to accept arbitration, the National Government imposed emergency regulations under the 1932 Public Safety Conversation Act which drastically curtailed civic liberties, including the freedom of speech and expression.

According to former journalist and historian Redmer Yska, Prime Minister Holland and his government exploited anti-Communist sentiment during the waterfront dispute.

Due to the Cold War atmosphere emerging in New Zealand, Holland was able to depict the watersiders as part of the "Red Peril" that was threatening Western democracy.

[17] After 1951 the National Government continued its policy of deregulating the economy by ending rationing on basic food commodities, loosening import controls, and encouraging home ownership by selling states houses to their tenants.

Holland's Government also reformed the superannuation scheme to enable retiring public servants to claim a portion of their entitlement as a lump sum payment.

[26][27] On the foreign policy front, the National Government embedded New Zealand in a series of Western Cold War security alliances and defence agreements.

[33] Once the National Government had been assured of a third consecutive term, Holland gave up the finance portfolio to Jack Watts, the former Minister of Industries and Commerce.

Also, the Tourist Hotel Corporation was established with Holland's strong support and against the opposition of Holyoake (by this time Deputy Prime Minister), who feared that tourism would divert investment away from agriculture.

[6][34] During Holland's last years in office, New Zealand also faced a serious balance of payments crisis that had been precipitated by a rapid decline in overseas demand for the country's butter, wool, and cheese exports.

[17] Amid the Suez Crisis in October 1956, Holland suffered a mild heart attack or stroke (accounts vary) while working in his office.

[37] He remained in Cabinet, as minister without portfolio; but he left the legislature for good at the 1957 general election, in which Holyoake went down to defeat, and which saw the advent of a second Labour Government under Walter Nash.