In 1940, Johnson won a by-election for Kalgoorlie.
 On the death of John Curtin in July 1945, he was elected by the parliamentary caucus to the ensuing vacancy in the ministry and he was appointed Minister for the Interior—which among other things was responsible for northern development—and Assistant-Minister for Works and Housing from 1945 to 1946.
 He was chairman of the Australian War Memorial's board of management from 1945 to 1949 and gained funding for its expansion to house collections from World War II.
 His appointment as minister lapsed with the defeat of the Chifley government at the 1949 election.
 He was unhappy with H. V. Evatt's leadership of the party during the 1955 split that led to the creation of the Democratic Labor Party and publicly expressed his concerns in 1957.
 This led the party to withhold endorsement of his candidacy at future elections, although he had already decided to retire at the 1958 election.
In 1940, Johnson won a by-election for Kalgoorlie.  On the death of John Curtin in July 1945, he was elected by the parliamentary caucus to the ensuing vacancy in the ministry and he was appointed Minister for the Interior—which among other things was responsible for northern development—and Assistant-Minister for Works and Housing from 1945 to 1946.  He was chairman of the Australian War Memorial's board of management from 1945 to 1949 and gained funding for its expansion to house collections from World War II.  His appointment as minister lapsed with the defeat of the Chifley government at the 1949 election.  He was unhappy with H. V. Evatt's leadership of the party during the 1955 split that led to the creation of the Democratic Labor Party and publicly expressed his concerns in 1957.  This led the party to withhold endorsement of his candidacy at future elections, although he had already decided to retire at the 1958 election.
Herbert Johnson (Australian politician)