Star Trek celebrity guest Don Most as Kadan in an appearance on Voyager in the episode called Workforce, part 1 and 2 and it takes place on Quarra.
The top picture is the actor in normal circumstances, and the bottom picture(s) is of the actor in their specific role(s).
Also once known as Donny Most, he is most well known for his role as Ralph Malph in Happy Days. He guest starred on many other TV shows too, so appearing on Star Trek was more or less inevitable.
Workforce Parts 1 and 2 -Star Trek: Voyager 262 and 263 - (episodes 7.16 and 7.17) -Playing Kadan -In the first part most of the Voyager crew have been kidnapped and their memories removed so they can be integrated into working on a planet named Quarra. The few remaining crew members must rescue them by applying for jobs on the same workforce. Tuvok starts to regain his memory and Torres is forcibly taken aboard Voyager. -In part 2 Janeway moves in with a co-worker, the issue of the EMH being a Command hologram comes up, and Kadan is found out to be the true culprit in this escapade. -Kadan is the doctor in the Quarren hospital that performs memory sequencing treatments on the Voyager crew and other beings on the planet to be integrated into their workforce.