O'Neill ended up doing another failed cop drama, this time a remake, "L.A. Dragnet." From there he had a gig on HBO's short-lived surf noir drama "John From Cincinnati" and did a David Mamet play — "I wanted something that was unknown, something out of my element. A half-hour comedy was the last thing I wanted to do," he said, referring to his current role on ABC's top-rated sitcom "Modern Family." "I just wanted to do independent movies. Something more strikingly different. Maybe later."
Naturally, actors from previous generations also wanted to move back and forth between comedy and drama in television – and some did. Buddy Ebsen starred in both the fish-out-of-water sitcom "The Beverly Hillbillies" and the straight-forward crime drama "Barnaby Jones."
Likewise, Carroll O'Connor turned Archie Bunker into a laughable bigot in the 1970s, and went on to play a southern sheriff in the police drama "In the Heat of the Night." But the dramatic roles, while popular in their time, typically operated in black-and-white worlds where bad guys were caught at the end of each episode - unlike some of today's more ambitious, demanding series which are centered on complicated, morally ambigious characters.
Often today, breaking the barrier between comedy and drama can come down to simple determination and luck, explained Cranston, who was intensely interested in playing Walter White in "Breaking Bad." Fortunately, Cranston had worked with show creator Vince Gilligan before on an episode of the "The X-Files."
"I wanted to go mark Vince," Cranston recalled. "I wanted to creatively lift my leg on him, and the script, and leave my scent so that he saw me and nobody else doing this. It's what I had been waiting for."
Another route for actors to transition between genres is to showcase their acting chops in a short stint or guest-star role, according to TV historian Tim Brooks. Typically, comic actors take this route, as John Ritter and Martin Short did on the dark procedural "Law & Order: Special Victims Unit."
Of course, Falco took the opposite path — heading from the deadly serious role of a mobster's wife to a lighthearted three-arc run as Alec Baldwin's character's love interest on "30 Rock." The move helped open the door to becoming the title character in Showtime's dark comedy "Nurse Jackie."
"I just wanted to use a different set of muscles," said Falco, who won three lead actress Emmys for her performance as Carmela Soprano. "It was more about me spending 10 years of my life playing the same character. What other people think I'm capable of is not my concern. Then 'Nurse Jackie' came along. It's not belly-laugh comedy, but it's so much more low-maintenance."
That's not to say it's any easier. The key, say actors, is not the genre, but the writing.
"I can't really say which is harder," Sagal said. "They both have their built-in challenges. With the comedies, I was working in front of a live audience and there was that adrenaline rush. There's something about the energy — you get an instant reaction to what works and what doesn't. But there's something beautifully scary about not having that too. To really channel the character in a more intimate level. But at the end of the day, you just do what's on the page."
And as the cable universe continues to expand and the four major networks become less cookie-cutter in their programming, television actors relish the chance to explore the full range of their skills — no matter the consequences.
"We're kind of gamblers, in a way," Dillahunt said. "It can be a colossal failure when we try something new. But actors hate being told they can't do something. It's all about the risk."