Career
He set his personal best of 2:08:09 hours at the latter race. Kinyanjui began competing internationally in 2002, mainly in American road races. He made his second appearance over the distance at the Country Music Marathon, setting a personal record of 2:15:52, although he was the runner-up on this occasion.
He was also second at the Fairfield Half Marathon but managed only ninth at the Virginia Beach Half Marathon.
Kinyanjui returned to Dallas and improved his best further to 2:14:35 hours, but was beaten to the title by half a minute by fellow Kenyan Elly Rono. He branched out beyond his United States base for the first time that year and was 13th at the Berlin Marathon, but he still ran a best time of 2:12:48 in the top-level race.
He began to focus on East Asian races from 2006 onwards. In a closely contested race, he defeated Georgiy Andreyev by one second at the Nagano Olympic Commemorative Marathon to record a personal record time of 2:11:18.
He was invited to the Beijing Marathon in October and he claimed first place with a significant new best time of 2:08:09 – over three minutes faster than he had run before.
He took a third consecutive title in Nagano the following year, narrowly holding off Tomohiro Seto in a four-man sprint for the line. He ran at the 2009 Dubai Marathon, but was well back in the field with his run of 2:15:23 hours. He did not race for the following two seasons and returned at the 2012 Prague International Marathon, placing fifth.