Before turning professional in 1999 Simon had many amateur successes, including winning the Finnish Amateur title, being runner-up of the national amateur match play golf championship for England (namely the English Amateur). Along with being a member of the Great Britain and Ireland Walker Cup Team in 1999, before turning pro later that year.

Since turning professional Simon has mainly played on the European Tour, with his professional wins including the Enjoy Jakarta HSBC Indonesia Open and two wins on the KLM Open.