Did Michael landon jr star in any little house episodes?

Michael Landon Jr. did not star in any "Little House on the Prairie" episodes. While his father, Michael Landon, starred in the show as Charles Ingalls, Michael Landon Jr. was not part of the cast. He was born in 1964, after the show started filming.

There was a character named "Little Joe" who was played by a young actor named Matthew Laborteaux. This may be the source of your confusion.