Even at age 24, in 1961, Berlinger was still playing wide-eyed youths, this time as the younger brother Buddy in the Broadway production of Neil Simon's "Come Blow Your Horn." Two years later, he made his London stage debut playing Finch, the junior executive, in the West End production of "How to Succeed in Business Without Really Trying". He did try a role of a different sort, essaying the title character in a summer stock stage version of "Tom Jones" in 1965. But subsequent theater work tapered off as the actor had settled in Hollywood, where he divided his time between films and TV. Berlinger has accrued credits in more than 1,000 episodes and TV-movies, dating from his small screen debut in an episode of "The Alcoa Hour" in 1951. From 1954-57, he was a regular on the CBS soap opera "The Secret Storm". Once settled in California, Berlinger played the kid brother on the first season of "The Joey Bishop Show" (NBC, 1961-62), had the title role of "Kilroy" in six segments of NBC's "Walt Disney's Wonderful World of Color" and was a regular on the short-lived "The Funny Side" (NBC, 1971). In 1973, he played son-in-law to Shirley Booth in the short-lived but very sweet series, "A Touch of Grace" and went on to appear on "The New Operation Petticoat" (NBC, 1978-83) and on "Small & Frye" (CBS, 1983).
Throughout this period, Berlinger was also making guest appearances on countless other series and appearing in such TV longforms as "The Girl Most Likely To..." (ABC, 1973), "The Red Badge of Courage" (NBC, 1974), in a rare dramatic role as a wiser soldier aiding Richard Thomas, and "What Price Victory" (ABC, 1988).
Berlinger first appeared in feature films playing the clean-cut teen who doesn't get the girl in "Teenage Rebel" (1956), but he did get another member of the cast, his future wife, Betty Lou Keim. He was an earnest young recruit in "The Wackiest Ship in the Army" (1960), beau to track star Patty Duke in "Billie" (1965) and took a nasty turn as Jewish gangster Gurrah Shapiro, a member of Murder, Inc., in "Lepke" (1974). He was wasted playing another Jewish character in "The Magician of Lublin" (1978) but fared better as the judge in Stephen Frears' "Hero" (1992).