At the 2015 IAAF World Cross Country Championships, Tirop became the second-youngest ever gold medallist in the women's race, after Zola Budd.

[3] Tirop first came to prominence at the national level in 2012, when she was runner-up to world junior champion Faith Kipyegon at the Kenyan Cross Country Championships.

[5] She was Kenya's most prominent entrant for the 5,000 metres at the 2012 World Junior Championships in Athletics and finished with a bronze medal in a personal best of 15:36.74 minutes, behind Ethiopian competition.

[11][12] Tirop was unable to achieve such a margin over runner-up Alemitu Heroye at the 2014 World Junior Championships in Athletics and was again third in the 5,000 m, while the Ethiopians extended Kenya's historic lack of a gold medal in that event.

[13] Tirop entered the senior ranks in the 2015 season and immediately performed well, winning the Eldoret Discovery Cross Country in Kenya.

This made the 19-year-old the second-youngest winner of that title in championships history, after Zola Budd's win in 1985, and also brought her Kenya's 300th medal at the competition.

[19] In 2017, Tirop participated in the World Championships held in London, winning the bronze medal in the 10,000 metres event,[20] with a time of 31:03.50, her personal best in the distance.

[25] Tirop was found dead in her home in Iten, Elgeyo-Marakwet County, on 13 October 2021; she had multiple stab wounds in the neck and abdomen.

[29] A search began for Tirop's husband, Ibrahim Rotich, when he went missing after calling his family crying and asking for God's forgiveness for something he had done.

He was then involved in a lengthy high-speed chase, trying to flee the country, and ultimately rammed his getaway vehicle into a truck near Mombasa.