His tenure in the ministry was interrupted by a brief stint in the Australian Army, which ended when he was recalled to cabinet following the deaths of three ministers in the 1940 Canberra air disaster.

Holt's father trained as a schoolteacher in Sydney and when Harold was born, worked as a physical education teacher at the Cleveland Street School in Surry Hills.

Holt's mother was born in Eudunda, South Australia, and had Cornish, English, German, and Irish ancestry; her sister was the actress Vera Pearce.

Holt generally spent school holidays with his relatives in Nubba or with schoolmates, rather than with his parents – his father had begun working as a talent agent, touring the country on the Tivoli circuit, while his mother died in 1925.

[5] Drawing on his family connections in show business, he eventually accepted an offer to become secretary of the Victorian Cinematograph Exhibitors' Association, a film industry lobby group.

[11] Holt was eventually elected to parliament on his third attempt, winning a federal by-election for the seat of Fawkner in August 1935; his predecessor, George Maxwell, had died in office.

[31] Menzies returned as leader of the UAP in September 1943, and Holt was initially a candidate for the deputy leadership; he withdrew once former prime minister Billy Hughes entered the race.

[6] One of his first acts was to intervene in the case of Lorenzo Gamboa, a Filipino man with an Australian wife and children who had been denied entry by Calwell due to his race.

He enjoyed good relationships with union leaders like Albert Monk, President of the Australian Council of Trade Unions; and Jim Healy, leader of the radical Waterside Workers Federation;and he gained a reputation for tolerance, restraint and a willingness to compromise, although his controversial decision to use troops to take control of cargo facilities during a waterside dispute in Bowen, Queensland in September 1953 provoked bitter criticism.

[51][d] A minor reshuffle occurred after the 1966 election, with Doug Anthony and Ian Sinclair added to cabinet and Charles Barnes demoted to the outer ministry.

[e] Labor ran on an anti-war platform, but struggled to appeal to voters concerned about national security; combined with Calwell's dedication to the White Australia policy, this allowed the party to be portrayed as isolationist and naive about external affairs.

Alan Reid asserts that Holt was being increasingly criticised within the party in the months before his death, that he was perceived as being "vague, imprecise and evasive" and "nice to the point that his essential decency was viewed as weakness".

[66] He was careful to frame his changes as simply a modification of existing policy, in order to avoid alienating organised labour (historically the greatest supporters of restricting non-white immigration).

[58] The Labor Party had only removed "White Australia" from its platform in 1965, and Opposition Leader Arthur Calwell stated he was "determined to continue to oppose, for many obvious reasons, any attempt to create a multi-racial society in our midst".

[77] Rupert Myer has suggested that "Holt's legacy ought to be a core belief in, and broad public demand for, the sustained support of cultural activity from all three tiers of government".

[83] This approach was disliked by his external affairs minister, Paul Hasluck, who in his memoirs accused him of believing in "instant diplomacy" and crediting his personal charms for advances made by diplomatic officials.

[85] He toured Cambodia, Laos, South Korea, and Taiwan in March and April 1967, and had planned to visit Burma, India, Indonesia, Japan, and Pakistan in 1968.

[87] There were also a number of reciprocal visits from East Asian leaders, including Eisaku Satō of Japan, Souvanna Phouma of Laos, and Thanom Kittikachorn of Thailand.

[86] The most controversial of those occurred in January 1967, when Prime Minister Nguyễn Cao Kỳ of South Vietnam visited on Holt's personal invitation – issued without consulting cabinet.

Public sentiment was beginning to turn against the war, and Ky's visit was met with large demonstrations; opposition leader Arthur Calwell issued a statement calling him a "miserable little butcher".

[94] By the end of the following year, however, opinion polls were showing that public sentiment had turned against the war, and previously supportive media outlets had begun to criticised Holt's decision-making.

[94] His replacement, Gough Whitlam, adopted a more pragmatic approach, focusing on policy specifics (particularly the government's apparent lack of an exit strategy) rather than the validity of the war itself.

Holt approved the construction of several Earth stations for use by NASA and American intelligence agencies, including Pine Gap, Honeysuckle Creek, and Tidbinbilla.

He repeatedly lobbied Wilson to maintain a strong British presence "East of Suez", in order to complement American efforts, and in early 1967 received assurances that no reduction was being contemplated.

[109] In May, increasing pressure from the media and within the Liberal Party forced Holt to announce a parliamentary debate on the question of a second inquiry into the 1964 sinking of HMAS Voyager to be held on 16 May.

The debate included the maiden speech by newly elected NSW Liberal MP Edward St John QC, who used the opportunity to criticise the government's attitude to new evidence about the disaster.

Support for his leadership was eroded even further by his refusal to sack the Minister for Air, Peter Howson, in order to defuse the scandal, fuelling criticism from within the party that Holt was "weak" and lacked Menzies' ruthlessness.

[112] On 17 December 1967, while Holt was spending the weekend at Portsea, he and four companions decided to drive to Point Nepean to watch sailor Alec Rose pass through The Rip on his solo circumnavigation attempt.

[126] According to biographer Tom Frame, it was an "open secret" that Holt was the biological father of the twins, as they shared his physical appearance and had been conceived at a time when Zara was known to have been in Melbourne.

It was launched by Holt's widow Dame Zara at the Todd Shipyards in Los Angeles on 3 May 1969, and was the first American warship to bear the name of a foreign leader.