(written from a Production point of view)
Stan Ivar (born 11 January 1943; age 73) is the actor who played Mark Johnson in the Star Trek: Voyager episodes "Caretaker" and "Persistence of Vision". He was also seen on photographs in the episodes "Eye of the Needle" and "Elogium".
Ivar was previously a regular performer on the TV shows Little House on the Prairie, Days of Our Lives, and General Hospital. He appeared in the 1989 movie The Big Picture, which also featured Stephen Collins from Star Trek: The Motion Picture and one-time TNG guest actress Teri Hatcher, and the 1991 movie Harley Davidson and the Marlboro Man (with Vanessa Williams, Jordan Lund, Branscombe Richmond, Brenan T. Baird, and James Nardini).