Horowitz became a national media personality when he became a regular television commentator during the 2004 Scott Peterson trial. Since the Peterson trial, Horowitz has been a commentator on other high-profile cases such as the Michael Jackson trial, the Melissa Huckaby trial in Tracy, California, and the Anna Nicole Smith case. He has appeared as a regular legal commentator on CNN, MSNBC and Fox News. In 2015, Horowitz was a commentator on the Orville Fleming case involving a California Fire Chief who killed his girlfriend and claimed that he was a "zombie" at the time of the killing and therefore was not guilty of premeditated murder. Horowitz was skeptical of the defense and the defendant was convicted. Daniel Horowitz was part of the Pfizer vaccine study and he strongly supported the safety and importance of the vaccination. Horowitz was featured on NBC and ABC news and was quoted by ABC's Kate Larson saying, "all reputable scientists say that it's safe and it's been proven safe in the trials. Take a little risk, be brave, and save your neighbor down the street."