Social media users and observers say Lekolool did his job well.
That service to Kenyatta ended at 1:09pm on Tuesday, when Dr Ruto formally took the reins of Kenya's leadership.
Immediately after Ruto received the ceremonial military sword from Kenyatta, Lekolool switched position and stood behind the new Commander-In-Chief of the Armed Forces.
That movement was beamed live to millions of viewers across the globe.
That moment was reminiscent of April 9, 2013, when Lieutenant-General Peter Njiru of the Kenya Army, took his position behind President Uhuru Kenyatta, who had been sworn into office to succeed Mwai Kibaki.
At the time, Njiru had the Colonel military rank. Due to his good service to Kenyatta and the disciplined forces, the former president, in July 2022, promoted him to the rank of Commander of the Kenya Army.
A president has the liberty to choose his or her Aide De Camp.
The serviceperson has to be a member of the Kenya Defence Forces (KDF).
Contrary to popular belief, the Aide De Camp is not a bodyguard or personal assistant to the Head of State.
Colonel Esther Wanjiku, the spokesperson of the Kenya Defence Forces (KDF), says the Aide De Camp is "a principal military officer serving the president".
"The Aide De Camp's roles include managing the president's diary and liaising with his or her main security team," Wanjiku told The Standard.
"The Defence Council can propose an Aide De Camp to the president, who has the last say on his preferred serviceman for the role," she added.
When foreign presidents visit Kenya, the KDF proposes servicepersons who would serve as Aides De Camp to the leaders.
The Kenyan Aides De Camp would work closely with the visiting Heads of State's military team.
Timothy Lekolool, who served Kenyatta, and is now serving Ruto, was first appointed as Aide De Camp in July 2018, when Victor Mburu, his immediate predecessor, flew out of the country to further his education.
Stay informed. Subscribe to our newsletter
At the time, Lekolool was a Lieutenant-Colonel in the Navy. He made history as the first Navy officer to hold the position.
His rank currently is that of Brigadier after he secured promotion in July 2022.
Lekolool is a married man with children, and is the first born son of former Provincial Commissioner Francis Lekolool, who died in 2013.
Timothy Lekolool was President Kenyatta's third Aide De Camp.
Functions of Aide De Camp
"Aide De Camp" is a term borrowed from the French language.
Its literal meaning is "helper in the military camp".
The holder of the position serves as an aide to a VVIP, in most cases a Head of State or Monarch.
An ADC is a highly-trained senior military officer, who is required to be part of the president's itinerary at all times.
The holder of the position mostly performs ceremonial duties.
Besides the ceremonial tasks such as standing behind the president and opening car doors for the Head of State, an Aide De Camp in Kenya has other duties.
For instance, during Uhuru Kenyatta's tenure, Lekolool was the detail leader, assistant detail leaser, tactical commander, motorcade lead, advance lead, mobile agent, static agent and protective intelligence agent.
Simiyu Werunga, the Executive Director for Geneva Centre for Africa Security, told The Standard that all Kenyan Aides De Camp held at least the rank of Colonel.
"Unlike the position of the Chief of Defence Forces, which rotates among senior military officers of the Kenya Navy, Kenya Air Force or the Kenya Army, the Aide De Camp's background is immaterial when the president is selecting the serviceman for that position," said Werunga.
"A new president can choose to retain the current ADC, or appoint a new one altogether."
Werunga further said that it's the responsibility of the Defence Council to propose ADCs to new presidents.
First female Aide De Camp
President Kenyatta oversaw a historical moment on August 17, 2018, when he appointed Kenya's first female Aide De Camp.
Lieutenant-Colonel Rachel Nduta was picked by the Head of State to serve as the Assistant Aide De Camp, deputising Timothy Lekolool.
That month, during an occasion, Nduta was seen standing behind President Kenyatta.
"President Uhuru Kenyatta [is] at the Kenya Music Festival Winners' State Concert. On duty, is the new Assistant ADC Lieutenant-Colonel Rachel Nduta Kamui from the Kenya Air Force, who will be working alongside Lieutenant-Colonel Timothy Lekolool." The State House tweeted.
Kenyan Aides De Camp
Kenya's first president Jomo Kenyatta's Aide De Camp was Major Marsden Madoka, who later served as Mwatate MP.
When Daniel Moi ascended to presidency in 1978 following Jomo's death, he inherited Major Macharia as Aide De Camp.
Macharia was later replaced by Major Peter Ngugi Ikenye, who was succeeded by Colonel Wilson Boinett.
Boinett, subsequently, rose to the position of Director-General of the National Security Intelligence Service.
After Boinett, came Colonel Alexander Sitienei, and then Lieutenant-Colonel Jonathan Rono.
Rono is currently the Major-General in charge of Eastern Command.
When Daniel Moi was retiring in December 2002, Stephen Boiywo was his Aide De Camp.
Boiywo was later appointed as a Commander of the Kenya Armed Forces. He was credited for ending the Sabaot Land Defence Forces menace in Mt. Elgon.
Moi's successor, Kibaki, started off with Lieutenant-Colonel Josiah Mrashui, a career engineer.
Mrashui was followed by Lieutenant-Colonel Godfrey King'angi.
Colonel Peter Njiru, Kibaki's last Aide De Camp while in office, succeeded King'ang'i.