An outrageously gifted age-group performer, the Keringet-based athlete is currently on top of the world after enjoying a near perfect 2017.
He first made his mark as a teenager back in 2011 by he securing the African U20 10,000m crown and later that year running the second quickest ever junior time for the 25-lap distance by storming to 26:55.73 clocking in Brussels.
In 2012 Geoffrey cemented his status as a top age-group performer by winning 10,000m bronze at the World U20 Championships in Barcelona.
In more recent times, he has focused his attention on the road.
In 2014 he finished second in 60:51 in his debut over the half-marathon distance in Lille and in 2015 twice dipped below the magic one-hour mark with times of 59:55 in Yangzhou and 59:38 in New Delhi for second and sixth, respectively.
After several attempts at marathon pacing, Geoffrey made his full marathon debut last April in Rotterdam placing third in a time of 2:07:23. Last autumn, in only his second race over the full 42.2km distance, he improved by almost a minute to run 2:06:27 to cross the line seventh in the Amsterdam Marathon.
The self-coached athlete emerged as a marathon superstar in 2017. In April last year, he trounced the opposition to win the Boston Marathon by a victory margin of more than two minutes in 2:09:37.
Then in August on the streets of London he further cemented his status on the global stage by destroying the opposition to be crowned World marathon champion in a time of 2:08:27.
In cold, wet and windy conditions, Geoffrey produced a brave attempt to defend his Boston Marathon title in April, but after leading for much of the race had to settle for second spot in 2:18:23.
Did You Know?
Geoffrey is the older brother of World U20 and World U18 steeplechase silver medallist Gilbert Kirui.