[1] A member of the National Party, he won the normally safe Labour seat as part of Robert Muldoon's landslide victory of 1975.

Walls was defeated after only one term by Labour's Stan Rodger; to date, he is the last National MP to represent Dunedin.

Following his defeat, Walls attempted to re-enter parliament by seeking the National nomination for the Auckland seat of East Coast Bays in a 1980 by-election.

He made the initial five person shortlist, but after being hospitalised suddenly, he was too ill to travel to Auckland for the selection meeting.

[5][8] He died suddenly in his Dunedin home on 30 October 2011 at the age of 74, and is survived by his wife June and three children.