'Dazed and Confused' Actor Nicky Katt Dead at 54

Nicky Katt -- a recognizable character actor who appeared in dozens of well-known shows and movies -- has died ... TMZ has confirmed.

Attorney John Sloss -- head of the firm that repped Katt, Sloss Law -- confirmed Nicky's death ... though he did not provide any more details.

Nicky got his start in acting way back in the early 1980s ... appearing in bit parts on "Fantasy Island" and "CHiPs."

After recurring rolls on "Herbie, the Love Bug" and "The Get Along Gang" in the mid '80s and grabbing a few more guest spots on "The Facts of Life" and "Uncle Buck," Nicky gained mainstream recognition for his part as Clint Bruno in "Dazed and Confused" ... a tough guy who fights Adam Goldberg's Mike Newhouse.

Nicky played a number of tough guy characters and unsympathetic villains over the years ... appearing in "A Time to Killer," "Sin City," "Boiler Room," "School of Rock," "The Way of the Gun," "Monk," "Law & Order" and many more movies and shows.

TV fans will probably most know him for his part as Harry Senate -- a teacher in the his show "Boston Public." Katt played the character in 49 episodes across the first three seasons of the show.

Many online are remembering Katt's talent ... and mentioning he always brought great performances to life onscreen -- while lamenting that he never quite became a household name.

Katt was married to a woman named Annie Morse from 1999 until 2001.

He was 54.