[1][2] Shalders entered the Royal Australian Naval College at Jervis Bay as a 16-year-old cadet midshipman in 1967.

After promotion to lieutenant commander in 1981, Shalders completed the Naval Staff Course for International Officers at the Naval War College, Newport, Rhode Island, and then undertook advanced warfare officer training in the UK, specialising in anti-submarine warfare.

Shalders commanded HMAS Perth in 1993–94 and attended the Royal College of Defence Studies in London in 1995.

On promotion to rear admiral in July 1999, Shalders was seconded to the Australian Customs Service as the inaugural Director General Coastwatch.

[4] On 23 May 2005, the Minister for Defence announced that Shalders would succeed Vice Admiral Chris Ritchie as Chief of Navy from July 2005 for a three-year term.