Level nine gymnast as well as swimmer, coral girl and cheerleader whose vlogs can be seen on her family channel, It's The Donnellys, which has earned over 1.1 million subscribers. She was a level 7 State Champion gymnast in all around, bars, beam and floor in 2016 before turning to cheerleading.
She became a YouTuber with her original Flippin' Katie channel in May of 2015 and accumulated over 100,000 subscribers in just three short months.
In just one month, her "The Great Watermelon Challenge(s)" video accumulated more than 2 million views. By early 2016, the video had over 13.2 million views.
Her older brother Brennan and younger brother Ryan are featured on her channel. Her parents are named Jill and Mike. Her boyfriend, Caden, has appeared on her family's YouTube channel.
She is joined by gymnast Arden Martino in The Coral Girls collective also known as Gymscool.