But the special assignment has plucked her from the relative obscurity of the cabinet office role to the beginnings of a public profile.
As one chief executive said of her: "It looks like she is going to be the new Margaret Bazley."
That's a reference to one of those people on whom all Governments come to need and depend upon as reliable fix-it-uppers or people who can get to the heart of a sensitive problem and offer sensible answers.
Whether Kitteridge would prefer to be compared to Dame Margaret Bazley or Stella Rimington, the former MI5 boss, we won't know: she politely declined to be interviewed for this piece.
What we do know is that Kitteridge is one of Key's four closest advisers.
Wayne Eagleson (also ex-Upper Hutt College) is his chief of staff, a political appointment by Key himself.
Then there are the three main officials: Andrew Kibblewhite is the chief executive of the Department of Prime Minister and Cabinet (DPMC), one of the three central agencies that has overview of the whole public service (with the State Services Commission and Treasury) and will often co-ordinate major issues involving several departments; Helen Wyn heads the policy advisory group with the DPMC giving Key policy advice on issues of the day; and Kitteridge is the secretary of Cabinet and Clerk of the Executive Council.
On any given day, these people can be the difference between the Prime Minister making a good decision or a bad one.
When Prime Minister John Key was informed by the Government Communications and Security Bureau on September 16 that it had breached the law in its surveillance of internet mogul Kim Dotcom at the request of the FBI, back in January, Key lost confidence in it.
The Inspector General of Intelligence and Security, Paul Neazor, stated in forgiving tones in a report to Key how the GCSB had breached the law because Dotcom was a New Zealand resident.
"In my view the only issue of illegality arises in this matter from confusion in this instance between the case of a person transferring funds and the general category of residents."
But to the sticklers for proper process, and one can safely assume Kitteridge is in that group, the GCSB broke the most basic principles of Government: that ministers and Government agencies must follow the law.
Adherence to the law is generally seen as being especially important in spy agencies because so little of what they do is open to scrutiny.
Key was not forgiving of the agency and let rip.
It didn't help Key's view of the agency that - after he had denied being so briefed - a record emerged some time later that the agency had mentioned Dotcom to the PM and a possible three other instances of illegal surveillance.
The head of GCSB, Ian Fletcher, and DPMC chief, Kibblewhite, needed a plan to restore his confidence.
It had to involve someone in whom the Prime Minister had complete trust.
It also needed someone who knew the public sector well, someone with integrity who could keep secrets, someone who could identify weaknesses in systems and change them if need be.
Kitteridge was the answer.
Fletcher and Kibblewhite jointly announced the secondment of Kitteridge to the temporary post of Associate Director of the GCSB and deputy chief executive.
Kitteridge became Secretary of the Cabinet in April 2008 but first worked in the cabinet office in 1997 when Simon Murdoch was head of the Department of Prime Minister and Cabinet.
She had attended Upper Hutt College - where her father was an English teacher - studied law at Victoria and had worked for one of the leading law firms, Chapman Tripp, in Wellington for nine years.
In 2001 she joined the legal division of the Ministry of Foreign Affairs and Trade specialising in constitutional issues in the Pacific - Fiji and Tonga probably provided her plenty of work.
In 2003 she went back to the Cabinet Office as Deputy Secretary to Diane Morcom and got the top job in 2008. She also has a husband and a 9-year-old daughter.
Kitteridge is described by former and current colleagues as "someone who does not take risks", "very straight" and "has a light touch and not at all pompous".
According to former head of DPMC Sir Maarten Wevers, the Cabinet Office is vocation for many dedicated people who just love the job and stay there.
"It's a bit monastical, the cabinet office," he says, "That's not a criticism. It's not like working for Telecom or Air New Zealand where you've got room to grow inside the organisation."
Kitteridge's role, he says, "is a position of great trust, confidentiality and discretion."
"Rebecca is the sort of person who always checks and double-checks and treble-checks. That is the nature of that role.
"Those qualities of very high trust and confidence and discretion, a complete focus on proper process, due process, and appropriate legal stuff, that is the mix of talent she will bring to that [GCSB] job and I think she will do it very well.
"She'll be saying 'who checks it, who double-checks it, how do you know this person is a New Zealander or not a New Zealander?'
"She will root it out and whip it into ship-shape."
In the Cabinet role Kitteridge reports directly to Key, giving him and his ministers advice and support on process, ethics, conflicts of interest, constitutional advice and generally the best way to make Cabinet decisions, at the Cabinet itself and at Cabinet committees.
That can mean sending Cabinet papers back if they don't adhere to the correct format or standard of consultation, perhaps if a minister or department is trying to rush something through.
You could say she is the No 1 guardian of a traditional process of decision-making, which, if it weren't there, might be faster but might be more dangerous.
In Monday's Cabinet, Bill English sits at the right hand of Key and Kitteridge sits on the left - the notetaker sits away from the table.
As Clerk of the Executive Council, Kitteridge gives direct advice to the Governor General on constitutional issues, and is particularly important before and after elections. She also oversees the honours system.
Privacy Commissioner Marie Shroff held the job for 16 years and first employed Kitteridge in the Cabinet Office.
She told the Weekend Herald that the job required discretion, independence, excellent judgment, strong values, respect for the rule of law, integrity, and being able to give advice fearlessly.
Shroff agrees it is a lonely job.
"At this level process is substance," she says.
What does she mean by that?
"I mean that getting a good quality decision made in a good quality way, properly consulted and with the right people involved at the right time, at the right places with the right ministers present, with everybody satisfied that they have the chance to have the input is the substance at the heart of the Cabinet process.
"Cabinet collective responsibility will only work if the process enables everybody to feel that they have had a fair go."
Shroff says the ability to manage relationships is also very important because of the high-pressure work environment.
"Ministers work under huge pressure. Nobody in New Zealand politics ever went into a Cabinet position for the good of their health or their bank balance. It is very, very demanding.
"That's one of the things about being Cabinet secretary. You are working with a group of people who are under huge pressure. So you need relationship management ability.
"You need excellent judgment because obviously the whole time there are difficult issues being managed."
It has been obvious to political observers and commentators that Key has been under greater pressure this term, not least during the drawn-out Dotcom debacle.
It is accepted in the Beehive that Kitteridge will go on to some other leadership role.
She has already been identified by the State Services Commission for a job heading a bigger Government department at some time, so the trouble-shooting job at GCSB is something of a test.
Wevers is confident the public can have confidence in what she'll be doing at GCSB.
"This is very reassuring for me because she is exactly the sort of person who can go in there and get out the broom and shovel and sort it all out, spic and span, and hand it back in good shape. That's what you need."
Rebecca Kitteridge
*Secretary of the Cabinet since April 2008
*Acting associate director of the GCSB since last month
*Aged 46, married, one daughter.
*One of Wellington's leading lawyers called "a professional's professional".
*Educated Upper Hutt College, left after 6th form for Victoria University. Arts, law degrees.
*Former convenor of the Wellington Women Lawyers' Association.
