Thacker was a member of the Christchurch Hospital Board (1907–1922),
Lyttelton Harbour Board (1907–1922),
Christchurch City Council (1929–1931) and Mayor of Christchurch between 1919 and 1923. The 1919 mayoral election was contested by Thacker,
John Joseph Dougall (Mayor of Christchurch 1911–1912) and
James McCombs (MP for
Lyttelton). Thacker contested the and general elections without success in the and electorates, respectively. He then contested the
Lyttelton by-election in 1913 as an
independent Liberal, coming fourth with 5% of the vote in the first ballot. Thacker was a member of the
Liberal Party and represented the
Christchurch East electorate in the
New Zealand House of Representatives from
1914. He was re-elected in
1919 but was defeated in
1922 by
Tim Armstrong from the
Labour Party, when he came second out of three candidates. In 1935, he was awarded the
King George V Silver Jubilee Medal. ==Death==