I Love Lucy
By 1951, the 64-year-old Frawley had appeared in over 100 movies, but was starting to find film offers becoming fewer. When he heard that Desi Arnaz and Lucille Ball were casting a new television situation comedy, he applied eagerly to play the role of the cantankerous, miserly landlord Fred Mertz. One evening, he telephoned Lucille Ball, asking her what his chances were. Both Ball and Arnaz were excited about including Frawley, a motion-picture veteran, in the cast; less enthusiastic were CBS executives, who were wary of Frawley's well-known frequent drinking and instability. Arnaz (himself a heavy drinker) warned Frawley about the network's concerns, telling him that if he was late to work, arrived drunk, or was unable to perform because of something other than legitimate illness more than once, he would be written out of the show. In one version of this conversation, Arnaz told Frawley he would get three chances. The first mistake would be tolerated, the second would result in a severe reprimand, and the third would result in his being fired. Contrary to the network's concerns, Frawley never arrived at work drunk, and mastered his lines after only one reading. Arnaz eventually became one of Frawley's few close friends.
Before each episode, Frawley would read the script with the rest of the cast, then would take out the sheets with only his lines and discard the rest of the script to study only his part.
I Love Lucy debuted October 15, 1951, on CBS, and was a huge success. The series was broadcast for six years as half-hour episodes, later changing to hour-long specials from 1957 to 1960 titled The Lucille Ball-Desi Arnaz Show (later retitled The Lucy-Desi Comedy Hour).
Vivian Vance played Ethel Mertz, Frawley's on-screen wife. Although the two actors worked well together, they greatly disliked each other offscreen. Most attribute their mutual hatred to Vance's vocal resentment of having to play wife to a man 22 years her senior. Frawley reportedly overheard Vance complaining; he took offense and never forgave her. "She's one of the finest girls to come out of Kansas", he once said, "But I often wish she'd go back there."
An avid New York Yankees fan, Frawley had it written into his I Love Lucy contract that he did not have to work during the World Series if the Yankees were playing. The Yankees were in every World Series during that time except for 1954 and 1959. He did not appear in two episodes of the show as a result.
For his work on the show, Frawley was Emmy-nominated five consecutive times (1953–1957) for Outstanding Supporting Actor in a Comedy Series. In 1957, at the end of I Love Lucy, Ball and Arnaz gave Frawley and Vance the opportunity to have their own Fred and Ethel spin-off series for Desilu Studios. Despite his animosity towards Vance, Frawley saw a lucrative opportunity and accepted. Vance declined, having no desire to work with Frawley again and also feeling that Ethel and Fred would be unsuccessful without the Ricardos.
