Is the main character who plays in TV show NCIS same guy that played Man From

You're likely thinking of Mark Harmon, who plays Leroy Jethro Gibbs in NCIS.

However, Mark Harmon did not play the Man From U.N.C.L.E. That role was played by Robert Vaughn in the original 1960s television series.

It's easy to see how you might get confused, as both actors have a long and successful career in television.