She started running in Spanish road races in 2004. She set a personal best of 71:19 minutes to win the 2005 Media Maratón Santa Pola and also won at the Granollers Half Marathon. She continued to compete at low level races and was runner-up at the 2007 Reims Half Marathon. She won that race the following year and improved her best at the Porto Half Marathon, running 70:43 minutes for third. She bettered that time at the 2009 Valladolid Half Marathon, taking the title with a run of 69:26 minutes, and was runner-up at the Porto race. She made few competitive appearances over the following 18 months, but won the Zhuhai Half Marathon on her Asian debut in December 2011. Cherono broke into the elite ranks in 2012. She was third at both the RAK Half Marathon and the Prague Half Marathon, recording a best of 68:18 minutes at the latter race. She also progressed on the track, taking the 5000 metres and 10,000 metres titles at the Kenya Defence Forces Championships. She was chosen to run these events at the 2012 African Championships in Athletics and, in the absence of higher profile athletes, she became the first woman to win both distance races at the championships. Her run of 15:40.04 minutes for the 5000 m gold medal was a championship record. She was not chosen to compete at the 2012 Summer Olympics and instead went on to win at the Bogotá Half Marathon and Tilburg 10K. She won the KenyaDefence ForcesCross Country title at the start of 2013, then ran a personal best of 1:06:48 to win the Prague Half Marathon – a time which brought her into the top 10 fastest women half-marathoner of all time. She won the national trial event for the 10,000 m and went on to take the silver medal behind Tirunesh Dibaba. She ended the year with runner-up finishes at the BOclassic and the Delhi Half Marathon. In September 2015, in her second time competing at the marathon distance, she won the Berlin Marathon in 2:19:25, which at the time made her the 7th fastest women marathoner of all time. Later in February 2016, Cherono finished the RAK Half Marathon in 1:06:07, which at the time made her the 4th fastest women half-marathoner of all time. In 2017, Cherono won her second Berlin Marathon with a time of 2:20:23. The following year, she won the Berlin Marathon for the third time with a time of 2:18:11 and set a course record. , Gladys Cherono is the 8th fastest women marathoner of all time and the 24th fastest in the half-marathon distance.
