He was a member of the Labour Party from 1954 to 1981, and stood in two general elections as a candidate; in and in . In 1960, he contested the "blue-ribbon" electorate and lost by 6109 votes to National's
Ronald Algie. In 1966, he contested the electorate and narrowly lost by 258 votes by National's
Rona Stevenson. He wrote that National was afraid of losing the seat so poured
thousands of dollars into the campaign. A hundred Waikato women canvassed every house in Tokoroa and Putaruru over two days, using the
street lists and blue dot system. In 1968 he joined the staff at Auckland University, and during his long tenure at Auckland he has authored several leading books on the topic of New Zealand politics. He wrote
Social Change and Party Reorganisation (1976) and
Labour’s Path to Political Independence (1980) while still a Labour Party member, but after completing
The First 50 Years: A History of the New Zealand National Party (1986) changed allegiance to National. In 1986 he also published
From the Cradle to the Grave: A Biography of Michael Joseph Savage. In 1975 he unsuccessfully sought the Labour Party candidacy for the electorate alongside 26 other aspirants following the retirement of
Hugh Watt, but lost to
Frank Rogers. In
1987 he stood as a National candidate for the
Birkenhead electorate to replace the retiring
Jim McLay, but was defeated by the
Labour candidate,
Jenny Kirk. During the 1990s Gustafson was given a number of international academic appointments, including visiting researcher at Stanford University and the European Union in 1990, and research at a number of
American and
British Universities in 1994. In 1997 Gustafson was
Fulbright Visiting Professor at
Georgetown University. From 1998 to 2002 Gustafson was appointed Head of the Political Studies Department, and he was also Pro
Vice-Chancellor (International) of the university from 2001 to 2002. In 2000 he published
His Way: A Biography of Robert Muldoon. Gustafson's teaching interests are predominantly the
European Union,
civil society, the development of New Zealand's political culture and parties, political leadership and power, and
interdisciplinary studies. For 25 years he also taught
Soviet and
East European Studies. In 2004 Gustafson retired as Professor of Political Studies, and was appointed acting director of the New Zealand Asia Institute, a position he held until 2006. In this time he helped to establish a
New Zealand Studies Centre at
Peking University. In 2007 he published
Kiwi Keith: A Biography of Keith Holyoake. ==Committee work==