Simon was born in Cambridge, Waikato, and has 20 years of experience as a finance professional working in large-scale, complex organizations across both the public and private sectors, primarily in the United Kingdom, New Zealand, Canada, and Ireland. His industry expertise spans healthcare management, global banking, and professional services.

Simon holds a bachelor's degree in management, accounting and finance, and health science. He served as Deputy Chief Financial Officer at the Waitematā District Health Board and at one point worked as a front-line ambulance officer for St John.

He has held roles in both the private and public sectors across New Zealand, Asia, and the United Kingdom. During the Global Financial Crisis, he worked for the Royal Bank of Scotland in London in various management roles.

Currently, Simon is the Minister for Climate Change and Revenues and is serving his second term as a Member of Parliament representing North Shore, Auckland, where he resides with his wife Shannon and their two sons.