The show, which premieres Tuesday night on NBC, follows three men as they meet 12 women handpicked by their matchmakers in their quest for true love.
This week she's also featured in the Cosmopolitan magazine article, "The Five Biggest Dating Mistakes You Don't Even Realize You're Making."
In an interview on the show's website, McMillan says that she's not a professional matchmaker or dating coach, but rather "a really good friend who's going to tell you the truth about the stuff you're doing that isn't working."
She also notes that she's had a "dramatic relationship history" and has been married and divorced three times, which leads people to question how she can tell anybody else what to do to get married.
"I'm like, 'Well, first of all, I'm very successful at getting married,' but the second thing is, 'You learn a lot from success, but you learn even more from failure,"' McMillan says.
McMillain has also written for several TV series, including "Mad Men," "United States of Tara," "Life on Mars" and most recently, "Necessary Roughness."
Her fellow matchmakers on the show include motivational speaker Matt Hussey and relationship expert Amber Kelleher-Andrews.
The show is hosted by reality personalities Bill Rancic ("The Apprentice") and Guliana Rancic (E! News).
See an interview with McMillan about how she was chosen to be a matchmaker for the series below.