Arnaz's TV-movie debut was actually one which is still talked about years later. In 1975, she played the title role in NBC's "Who Is The Black Dahlia?", based on the true story of a mysterious murder of a would-be actress and part-time prostitute whose horrific slaying in the 40s has yet to be solved by the L.A. Police Department. That same year, Arnaz starred for ABC in "Death Scream", inspired by the true-life murder of New Yorker Kitty Genovese. In 1980, she was back on CBS in "The Mating Game", but, by 1988, was decidedly a supporting player, the one friend who sticks by Jill Clayburgh after her divorce, in "Who Gets the Friends?" (CBS). Arnaz also had two other tries at primetime series: her own sitcom "The Lucie Arnaz Show" (CBS, 1985), in which she played an advice columnist, and "Sons and Daughters" (CBS, 1990-91), an ensemble drama about a family in Portland, OR. Arnaz has also made several attempts to launch herself in a daily chat show, but they have never gotten past the pilot stage. She is, however, a frequent guest on talk shows. In 1995, she played Auntie Em in the TNT concert version of "The Wizard of Oz".
Arnaz never cracked the feature world. Her first film, "Billy Jack Goes to Washington", a sequel in to the popular Tom Laughlin vehicle, was made in 1977 but never released. In 1980, she was the "shiksa" in the life of Neil Diamond's "The Jazz Singer" in the third (and unnecessary) remake. Stage work has provided steadier employment. Arnaz appeared with the San Bernardino Light Opera Company in "Cabaret" in 1972. She headlined as Gittel Mosca, the neurotic dancer who romances a lawyer in the 1974-75 national tour of Michael Bennett's "Seesaw", adapted from William Gibson's "Two for the Seesaw". Arnaz made a heralded Broadway debut opposite Robert Klein as competing yet loving songwriters (based on Carole Bayer Sager and Marvin Hamlisch) in the Neil Simon musical "They're Playing Our Song" (1979). She has since appeared throughout the country in productions ranging from "Annie, Get Your Gun" to "Once Upon a Mattress" as well as developing a cabaret act she has played in Atlantic City, Las Vegas and elsewhere.
After the 1989 death of their mother, Arnaz and her brother, Desi Jr., formed Desilu Too, a company created to manage and exploit the properties and legacy of their parents. Arnaz also is partnered with her husband, actor Laurence Luckinbill, in Arluck Prods. Through the latter, she and her husband were executive producers of "Lucy and Desi: A Home Movie", snippets from behind the scenes with Lucy and Desi which won an Emmy for Best Informational Special in 1993.