But what really sets the 22-year-old former Miss Teen Pennsylvania International apart from others in her field is her meteoric rise from Villanova University student to major-market TV personality, which she accomplished in what has to be record time.
Generally, making it to a Philadelphia TV station requires years of dues-paying in broadcasting backwater markets like Pierre, S.D. or El Paso, Texas. But not for McDonnell, whose traffic reports are a major part of the "Good Day" daily presentations.
Upon graduating from Villanova with a communications/journalism degree, McDonnell - who during school worked on air at the QVC home-shopping channel, in West Chester - got herself a media coach and also did some modeling, although she never deluded herself that she could succeed in that realm.
"I wasn't looking to be a model. All 5'4" of me was not looking to be the next Adriana Lima," she said, referring to the Brazilian supermodel, during a recent lunch at Old City's Fork. "That would be my dream come true, but that wasn't reality. I always knew I wanted to be in entertainment, in sports broadcasting, in news - one of those three areas."
Nonetheless, she did some modeling, which led to a TV commercial for Fiat of Maple Shade, in South Jersey (see it here: ph.ly/-StDo).
During this time, she was also training to be a TV traffic reporter at Radiate Media, a Malvern-based traffic-monitoring clearinghouse. Last spring, she "was getting ready to send to Idaho and Mississippi and South Dakota, and this job came up."
McDonnell applied for the gig. She started on Aug. 20. She said that her lack of experience has never been an issue with the "Good Day" team headed up by anchors Sheinelle Jones, Mike Jerrick and Karen Hepp.
"There has not been an ounce of any bad feelings or ill will, not at all," she said. "They accepted me with open arms. I'm kind of like the little sister of the group. We're totally a family.
"Definitely, there was something to prove, being right out of college, but I think slowly, and with the help of everyone at the station - on air and behind the scenes - I'm starting to figure out who I am on a professional level."
In an email, "Good Day" executive producer Maryann Vaughn wrote: "Kacie brings a ton of energy to the show (even at 4:25AM)! She is definitely one of our rising stars."
Another fan is Jerrick, who wrote: "Obviously, she is attractive, but her value to us and our viewers is her intelligence, work ethic and good nature. She has a bright future in this business. I'm so glad she has joined the 'Good Day' family."
Although landing the job was quite a coup for someone so young and relatively inexperienced, it hasn't come without a price: Because she's on the crack-of-dawn patrol (the show runs from 4:25 to 9 a.m. weekdays), her daily schedule is not that of most people her age. She is in bed between 6 and 8 p.m., "depending on how bad I'm breaking the rules," and at Fox's Old City studios by 4:08 a.m.
Nonetheless, McDonnell, who described her relationship status as "single," insisted that the schedule hasn't cramped her style too severely, noting that she can often be found out on the town with friends.
Though thrilled with her current post, McDonnell's ambitions don't end with telling people about accidents on the Schuylkill Expressway.
"If I could get a big melting pot and throw Oprah and Ellen and Erin Andrews and Giuliana Rancic into the pot and mix it all up, that's what I want to be - the combination of entertainment and sports reporter and do-gooder/show host," she said.
"But I am totally fascinated by football. I think it's the coolest, greatest thing. They say if you can't do . . . report on it. They're not gonna let me out on the field, and I don't think I'm gonna get a coaching job any time soon, but if I could be the next Erin Andrews, sign me up, check it off the list.
"I'm there, I'm your girl."
On Twitter: @chuckdarrow