• The death of his father, Tom Harmon, in 1990.
• Long-running family tensions involving his late sister, Kristin Harmon, including a highly publicized custody dispute years earlier.
• The intense workload and burnout he later described after spending nearly two decades starring in NCIS, which contributed to his departure from the show.
• 

Many videos using that exact wording imply that Harmon became withdrawn or changed after personal losses, but there is no widely documented event where he publicly said, “I was never the same afterward.” Much of that framing comes from entertainment media exaggeration rather than Harmon’s own statements.

Interestingly, one dramatic real-life event often associated with him is the opposite: in 1996, Harmon helped rescue a teenager trapped in a burning car outside his home, an act for which the survivor later credited Harmon with saving his life.