She was eventually promoted from the personal assistant position to have more involvement with Kim Kardashian West's brands—think KKW Beauty, KKW Fragrances and Kids Supply. Her last official title with the family was as the Chief Operating Officer of all Kardashian West Brands, which is a fairly coveted position bearing in mind the large amount of money that anything brandished with the Kardashian name makes.
However, after over five years of working for Kim, Shepherd was 'let go' at the end of 2017—and the drama was aired on an episode of Keeping Up With The Kardashians, naturally.
It began with Shepherd confiding in Kourtney Kardashian that she felt "unfulfilled career-wise," and Kourtney reported this back to Kim who did not take the news well—deeming Stephanie unprofessional for not coming to her with this information, and instead, talking behind her back to her own sister.
In the same episode, Kim confronts Stephanie who responds by defending her statement, saying she's just in an awkward in-between life-stage where she's not "22 and starting out with my career, or married and having babies", leaving her confused about what she should do next.
It seems that a combination of job-dissatisfaction and the awkward crossing-the-boundary of their personal and working relationship ultimately led to Shepherd being let go. Though it became fairly common knowledge, it's only now that Kim is speaking up about the professional fall out.
In the most recent episode of Keeping Up With The Kardashians, Kim speaks on the phone to her good friend, Allison Statter, about the breakup between her and Shepherd.
"I said, 'I love you a lot, like a sister, and this conversation is really hard for me to have. But I just think that you've outgrown your position here. She was like, 'I totally get it and I totally respect you and you've taught me everything. I'm so grateful and I've been with you for five years.'"
"Stephanie and I have decided to part ways. She wanted a different role and I was going in a different direction, so for both of us, I just felt like it wasn't the right fit anymore... She's really been there for me. So I said, ‘I love you so much, and maybe this is good to push you to figure out what you want to do.’ It ended really well. She knew that she needed this time and that it wasn't working."
It all appears to have 'ended well'. Kim and Stephanie have appeared on each other's social media together since the split. Ms. Kardashian West sent Shepherd a smash cake for the launch of her KKW Valentine's Day fragrances, with Stephanie captioning the photo, "@kimkardashian <3." Shepherd also attended the extravagant island birthday party that the Kardashian sister had to celebrate her 40th birthday.