Born in Machakos, he was the son of a javelin thrower, David Ndiku, but he decided not to follow his father and focused on running instead.

[1] He began his career in domestic cross country running competitions and at the Athletics Kenya series meeting in Meru, he took fifth place in the junior men's race at the age of sixteen.

[5] Ndiku returned to the Kenyan cross country circuit at the end of the year, and finished fourth at another Athletics Kenya series race in Nairobi.

He won the junior title and also headed the Kenyan runners to the team gold as the country grabbed the top four spots.

He began competing in senior competitions the following year and was runner-up at the Trofeo Alasport cross country in March, second only to the newly elected world champion Imane Merga.