In 2001, he entered both the Super 1 National JICA Championship and the Trofeo Andrea Margutti ICA Junior, finishing eleventh and 23rd respectively.

[2] In 2005, Keen moved into the Formula BMW UK series driving for Team SWR Pioneer, and finished on the podium once from four races.

[2] He then switched to the Formula Renault 2.0 UK series, driving for Team Firstair, and finished fourteenth in the championship standings, with 130 points from sixteen races,[2] and won the Graduate Cup.

[6] He also entered the Formula Renault 2.0 UK Winter Series in 2006 for Fortec Motorsport, taking a podium and finishing sixth overall.

[2] In 2007, Keen entered six rounds of the Formula Renault 2.0 UK for Apotex Scorpio Motorsport,[2] alternating with David Epton during the first half of the season.