[1] Mutai grew up in Cheptigit, a village near Kaptagat, Uasin Gishu County in the Rift Valley Province, and his extended family includes Richard Limo, the 2001 World Champion over 5000 metres.

[2] Mutai began to make an impact domestically at the age of eighteen, taking third place over 10,000 metres at the Rift North Province Championships in 28:09.2 minutes.

[3] It was on the roads of Europe that he began to make a name for himself, beginning with a win at the Nice Half Marathon in April 2006[4] and then a 10K best of 27:51 minutes for second place at the 10 km du Conseil Général 13 behind Edwin Soi (one of the fastest runs that year).

[9] He defeated strong opposition in Robert Kipkoech Cheruiyot and world champion Jaouad Gharib at the Portugal Half Marathon in September, winning the Lisbon race with a quick finish.

[15] His final run of 2008 was at the Chicago Marathon and he began strongly, pushing the race tempo to the point where he forced the pacemaker to prematurely drop out.

[18] At the 2009 London Marathon he posted his third sub-2:07 time, but again this left him in fourth place in the perennially fast race while Samuel Wanjiru broke the course record.

It was Kirui who took the lead to claim the title, but Mutai took the silver medal in a time of 2:07:48 hours, which was the second fastest ever run at the event.