Born in Christchurch,[1] Steer joined the Royal New Zealand Navy in 1973.

[2] He served as chief of staff at Joint Forces Headquarters from January 2003 to April 2004, when he was promoted to commodore and appointed as Maritime Component Commander.

[2] He was appointed Deputy Chief of Navy in January 2006, before taking up the position of Commander Joint Forces New Zealand in May, with promotion to rear admiral.

In February 2008, he was appointed Vice Chief of Defence Force.

Steer was appointed an Officer of the New Zealand Order of Merit in the 1996 Queen's Birthday Honours.