Holding joined the Labor Party as a student, and during the Labor Party split of 1954–55, during which he supported the party's federal leader, Dr H.V. Evatt, he was Secretary of the Young Labor organisation in Victoria. As a young lawyer he was a prominent campaigner against the death penalty and in favour of the rights of indigenous Australians. His law firm, Holding, Ryan and Redlich, became one of the leading industrial law firms in Melbourne.
State politics
In 1962 Holding was elected to the Victorian Legislative Assembly for the seat of Richmond, which had previously been held for many years by mostly conservative Catholic Labor Party members, although his immediate predecessor, Frank Crean, was a Presbyterian. Clive Stoneham, who had been ALP leader from 1958 onwards, was no match for the dominant LiberalPremier, Sir Henry Bolte. After Labor suffered its fifth consecutive defeat at the 1967 election, Holding took over from Stoneham as party leader. Although Holding was in some ways a social radical, he was opposed to the left-wing faction which had taken control of the Victorian Labor Party following the 1955 split, which had seen many right-wing members expelled. In particular, he supported government aid for non-government, including Catholic, schools, which the left bitterly opposed. He was a supporter of the reforming federal Labor leader, Gough Whitlam, who was determined to reform the Victorian branch as a precondition of winning a federal election. He was also a close ally of the ACTU president, Bob Hawke. During the 1970 state election campaign, which some commentators suggested Labor could win as a result of voter fatigue with the Liberal government after its 15 years in power, Holding campaigned on the new federal policy of supporting state aid to non-government schools. The week before the election, the left-wing state president, George Crawford and state secretary, Bill Hartley, issued a statement saying that a Victorian Labor government would not support state aid. As a result, Whitlam refused to campaign for Labor in Victoria, and Holding was forced to repudiate his own policy. Ultimately, the Bolte government was re–elected, but Holding did manage a six-seat swing. This episode led directly to federal intervention in the Victorian branch of the Labor Party. In 1971 the left-wing leadership was overturned by the Labor National Executive and allies of Whitlam, Hawke and Holding took control. The left then formed an organised faction, the Socialist Left, to agitate for socialist policies, supported by some unions. Bolte retired in 1972 and was replaced by Dick Hamer, a considerably more progressive Liberal from Melbourne. Hamer represented such a sharp change from his staunchly conservative predecessor that he was able to brand himself as a reformist leader even though the Liberals had been in office for 17 years. Holding was unable to get the better of Hamer, and was roundly defeated at the 1973 and 1976 state elections. The surge in support for federal Labor, which saw Whitlam elected Prime Minister in 1972, was not reflected in Victorian state politics.
Federal politics
Holding resigned as Opposition Leader after the 1976 election to transfer to federal politics. In 1977 he was elected to the House of Representatives for the comfortably safe seat of Melbourne Ports, which then included Holding's base in Richmond. He defeated Simon Crean, son of Holding's predecessor, Frank Crean, to win Labor pre-selection. After the 1980 election, at which Hawke was elected to federal Parliament, Holding emerged as Hawke's key "numbers man" in his campaign to become leader of the federal Labor Party.
Melbourne Ports was significantly altered ahead of the 1990 election. Long one of the safest Labor seats in the nation, it was pushed slightly to the east to take in some wealthier, Liberal-leaning suburbs. This knocked Holding's majority from a reasonably safe 9.9 percent to a marginal 3.9 percent. Nonetheless, Holding was re–elected with a small swing against him. He remained in the House as a backbencher until his retirement in 1998.