After being elected in 2015, the mother-of-two’s time was split between London and her West Yorkshire constituency, where a hectic schedule of meetings and appointments awaited her.
The demands of her job meant Jo would frequently lean on her family and aides Fazila Aswat or Sandra Major for help with day-to-day tasks.
“Dad would feed her and inevitably she would come round to me or mum, or Fazila or Sandra, and say ‘I haven’t got any make-up, I haven’t got any clothes, what can I borrow?’,” recalls Kim, speaking to The Yorkshire Post at her home in Gomersal.
“That was just classic Jo, she was always thinking about the big picture, the major issues, so the day-to-day stuff just got totally forgotten.
“We were just getting into a really lovely routine of me going down to London, helping out with the kids down there, her coming up here, mum and dad having the children.
“When she first started she would be booked out with appointments from first thing in the morning to 10 at night. It got to the point where Fazila said, ‘look Jo, you are going to run yourself into the ground here if you are not careful, you will end up totally exhausted’, which she did.
“So Fazila stopped booking appointments beyond 7pm at night. She would then say, ‘go and see your sister, see your mum and dad’.
“The week before she was killed she came round here, Jo walked through the door, normal exhausted Jo, and took her smart clothes off, and said, ‘can I borrow some clothes?’.
“So I got her one of my hoodies, and some pyjama bottoms, and I made her some tea, and she snuggled up in that chair, she was a tiny little thing, and we chatted, and we had a lovely time actually.
“That would have been happening more and more regularly, and that’s what is really sad. It’s a lovely memory, and I am so lucky because I don’t have anything but positive memories.”
Kim, who is organising a series of events in Yorkshire to keep her sister’s memory and values alive, is keen to talk about the murdered MP not just as a politician, but as a sister, mother, daughter and wife.
Growing up in Heckmondwike with a two-year age gap between them, Kim and Jo Leadbeater were close and did a lot of activities together, whether it was Brownies or cycling on BMX bikes.
“What people don’t realise is that she was really shy when we were kids, so I was the one who would take the lead with everything, whether it was calling up for a bus timetable, or ordering a takeaway, or any of those simple things in life,” Kim recalls.
“She was shy, but that was what made it so impressive, what she achieved, she had to really work at that. Even academically, she was extremely bright but had to work very hard to achieve what she did, getting into Cambridge.
“Jo really struggled with public speaking for a long time, which makes it all the more impressive that she went as far as she did. It was hard work that got her there, proper Yorkshire grit and determination.”
After several years working for Oxfam and taking on a role advising Sarah Brown, the wife of former Prime Minister Gordon Brown, Jo decided to try and get into politics, standing in the seat vacated by former MP Mike Wood.
“Mum and dad and I had said, ‘look Jo, we will support you 100 per cent but we want to be in the background. We don’t want to be front of house’,” said Kim.
“Jo came to us and said ‘I am thinking about going for the job’. Mum said, ‘absolutely fine, as long as it won’t change our lives’.
“To look back on that now is just the strangest feeling, because we laughed and joked about it all the time, because Jo said ‘it won’t affect you, don’t worry’.”
Those words took on a cruel irony on June 16 last year when Jo was murdered by a far-right extremist outside her Birstall constituency office.
Kim recalls the events of the following weeks and months as a blur. She and family were forced to deal with a pain she describes as being like when “you literally feel your heart breaking”, an experience only those who lose someone in such circumstances can relate to.
At the same time there was the police investigation going on, as well as efforts to protect Kim and her family from possible danger.
Her locks were changed, extra smoke alarms were fitted, a device was installed to stop things being pushed through her letter box and checks were made about her regular running routes.
“I have never felt scared in my whole life and all of a sudden you are thinking ‘this is real and I’m scared, and my confidence is knocked’,” she recalls.
“You have this hyper-sensitivity, where you think ‘what if something happens to me’, and you think about your mum and dad, so everything is heightened.”
Despite the trauma of the last nine months, Kim, a 40-year-old lecturer, can look back with pride and pleasure on the time spent with her older sister.
“We can look back and say we had the best relationship we could have done, I had the best sister I could have had, and also Jo wouldn’t have had any regrets about her life.
“She lived it to the full, and she wouldn’t have regretted taking the job, because it was what she wanted to do.”