Meredith achieved iconic status for playing The Penguin in the television series Batman. His role as the Penguin was so well-received that the show's writers always had a script featuring the Penguin ready whenever Meredith was available. He appeared on the show more times during its run than any other villain except for Cesar Romero's Joker who tied with Meredith for number of appearances on the show.
From 1972 to 1973, Meredith played V.C.R. Cameron, director of Probe Control, in the television movie/pilot Probe and then in Search, the subsequent TV series (the name was changed to avoid conflict with a program on PBS). The series involved World Securities Corporation, a private agency which, among other activities, fielded a number of detectives equipped with high-tech equipment including a tiny TV transmitter (the "Scanner") which allowed Probe Control to see what was going on where the agents were working. One episode centered around Cameron being kidnapped and having to escape from a torture chamber, without any of the tools carried by Probe agents.
He won an Emmy Award as Outstanding Supporting Actor in a Comedy or Drama Special for the 1977 television film Tail Gunner Joe, a fictitious study of U.S. Senator Joseph R. McCarthy, the anti-communist leader of the 1950s.
In the early 1980s, he was also a co-host of the ABC program, "Those Amazing Animals," along with Fran Tarkenton.