He finished his début season 42nd on the Order of Merit, and was named the European Tour's Sir Henry Cotton Rookie of the Year.

[4] At the end of the year, he partnered Colin Montgomerie to second place for Scotland in the 2006 WGC-World Cup, after losing out to Germany in a playoff.

[5] In 2007 Warren captured the Johnnie Walker Championship at Gleneagles, after overcoming Simon Wakefield on the second hole of a sudden death playoff.

In July 2012, Warren had an opportunity to win his home event, the Scottish Open at Castle Stuart Golf Links.

He birdied the first four holes on the back nine during the final round to go into a one shot lead, but bogeyed 15, then parred his way in to make the playoff with Simon Khan and Matteo Manassero.