Which actor has had the best success after his or her breakout series?

Cafe Society
61

I believe Sara Michelle Gellar was in a soap too. And a Wendy’s commercial.

I wouldn’t call it a breakout role but Ben Affleck was in a “blink and you’ll miss it” scene in the movie Buffy the Vampire Slayer, and he did a commercial too (Burger King).

And John Cryer has done pretty well in 2 1/2 Men after doing mostly nothing since Pretty in Pink. Ashton Kutcher, on the other hand, is slumming it.

I’d like to give a special shout out to Sam Huntington, who got his start in “Not Another Teen Movie” just for looking like the guy he was parodying, to having a very juicy role in the USA version of Being Human.

62

And Kate Mulgrew and Yasmin Bleeth, who played Mary Ryan Fenelli and her daughter Ryan on Ryan’s Hope.

63

I remember Joseph Gordon-Levitt from when he was Tommy Solomon in Third Rock From the Sun.

64

In one of the teen magazines in the 1990’s, when Olyphant was being interviewed for Scream 2, he mentioned off-hand that he was the only cast member not being besieged by fans for autographs.
15 years (+/-) later, and he’s more well known than anyone else in Scream 2.
(with the possible exception for Sarah Michelle Gellar)