In June 2025, she became the second woman in the history of the Kenya Defence Forces to attain the rank of a Major General following her promotion by President William Ruto.
By so doing, she equaled the record that had stood for seven years and held by former Kenya Air Force commander Major General Fatuma Gaiti Ahmed, who had become the first woman Major General in Kenya.
Major General ( Rtd ) Ahmed attained the two-star general status in 2018 following her promotion by the then President Uhuru Kenyatta.
Today, Major General Sitienei is an accomplished woman in the military, being the highest ranked female in KDF, and the only one with a rank of a two-star general.
In 2025, she was appointed as the Deputy Vice Chancellor in-charge of Centre for Security and Strategic Studies at the National Defence University-Kenya.
Prior to that, she had spent nearly her entire military career at the International Peace Support and Training Centre, the institution she headed for four years since her appointment in 2021.
For four years, from 2016 to 2020, she served as the Colonel, plans and policy at the International Peace Support and Training Centre. Before that, she was in-charge of applied research in the same institution.
From 2010 to 2011, she was the director of research at the IPSTC.
Major General Sitienei who joined KDF as an education officer, had previously served in the position at the 15 Kenya Rifles in 2001. Before that, she served in the same capacity at the Women Service Corps.
Before joining the military in 1995 as an Officer Cadet, Major General Sitienei worked as a teacher at Longisa Secondary School.
She graduated with a Bachelor of Education ( Arts ) degree in religious studies from Kenyatta University.
She is also a holder of a Masters degree in International Studies from the University of Nairobi.
Major General Sitienei has also trained extensively in military studies from various institutions, including the National Defence College.