Many were former students of her father's, including students dating back to the 1960s.
"[There were] all these memories of him in the classroom and how they may not remember much about St Thomas, but they remember so much about Professor Krohn ... that he's the most kind-hearted, most compassionate person you'll ever meet," Julia told Good Morning America."
Krohn and his wife Chesley have been married for 54 years and have four children and six grandchildren.
"He's an actor as well so that has gone hand and hand in his teaching," Julia said. "He's just so lively and it's like watching a performance."
Houston's University of St Thomas has adopted an e-learning model amid Covid-19.
After having technology issues, Julia invited her dad to her house so he could use her computer.
Julia said she hadn't seen her dad teach in 20 years.
"The fact that [he's teaching] virtually and still engaging and so smart and so quick ... it was just this beautiful moment that I just had to capture," she added.
After reading every single Facebook comment, Julia said her father was brought to tears.
"Professor Krohn was my UST English professor in Fall '92 and Spring '93," one former student wrote.
"And right now he is my daughter's UST English professor."
"He taught me so much & opened up a new world of literature," another commented.
"His passion and dedication were not unnoticed. I'll never forget my experience w/ Krohn."
Krohn's computer is now fixed and his daughter said he hasn't missed a beat.
