Running Man made the members much more popular, but some of them were already popular in their respective fields.

That includes Yoo Jae Suk, Kim Jong Kook, HaHa, and Kang Gary.

Yoo Jae Suk was unknown for a very long time before gaining massive popularity, now he's revered for his MC skills and is one of the (if not the most) likable, most famous hosts/comedians.

Kim Jong Kook was famous not only as a singer but involved in many other variety shows that were popular as well.

Kang Gary, LeeSSang was already well established. Running Man did help him with his image as variety shows tend to do that. I always thought it was funny how he worked with YJS and HaHa on Running Man while the other half of LeeSSang, Gil worked with them on Infinite Challenge.

Ji Suk Jin was already involved in shows, but I wouldn't say he had any international fame. He was the host of Star Golden Bell and that was really popular.

The members it helped garner attention to popularity wise was to Song Ji Hyo and Kwang Soo, especially internationally making them "hallyu." Although Ji Hyo had been apart of popular dramas I don't think she was very sought after or a popular actress (especially as a main lead) and Kwang Soo was completely unknown.

Running Man definitely did help all of them, some more then others, but 4/7 would have had inevitable success. '

If you look at someone like Lizzy who was on the show but then left, it didn't negatively affect her but think of how much more successful she would have been if she was the only permanent idol on Running Man. Especially through their golden era. Of course, there's also someone like Song Joong Ki who also left but found success through his roles in acting.