Kate McKinnon joined SNL in April of 2012, a short 2 years after I saw her perform at the Upright Citizen's Brigade Theatre in New York. Absolutely no coincidence there. It did not take her long to break through on SNL, moving from being a featured player to full cast member. It also did not take her long to be given roles in numerous comedies over the years and do voicework on animated shows (e.g. PBS's Nature Cat). If you watch SNL, I'm sure you love Kate McKinnon's work. From the accents, to the eccentric characters, to the bravado and swagger.
Vanity Fair's November, 2017 issue features and profiles Kate as their cover story. It's an interesting longform read. I must warn you that the profile does drift away from McKinnon at times, going on tangents about Alec Baldwin's Trump impression and SNL's other takes on politics.