Phillips was born Lily Renee Willhelm in 1921 to a prosperous Austrian Jewish family; her father was a manager for the Holland America ship line. After the Nazis occupied Austria, the British set up a program called the Kindertransport to bring at-risk children out of the country. Phillips left on one of the last ships and spent two years in England. When her parents arrived in the U.S., in about 1940, Phillips traveled there to join them. Although still a teenager when she arrived, Phillips was a talented artist, and she began working in commercial art in order to help support her family, doing advertising and catalog art. She also took art classes at the Art Students League and the School of Visual Arts.
In 1942, Phillips answered a classified ad placed by Fiction House and wound up working there. Her comics work there included drawing “Jane Martin” in Wings Comics, “The Werewolf Hunter” in Ranger Comics, and perhaps her best known work, the Nazi-fighting Brazilian nightclub entertainer “Senorita Rio,” in Fight Comics. Fiction House comics were pulpy, but as writer and historian Trina Robbins noted in her book Pretty in Ink: North American Women Cartoonists 1896-2013, “The six Fiction House comic book titles – Jumbo, Jungle, Fight, Wings, Rangers, and Planet – specialized in luridly sensationalistic stories with strong and beautiful female protagonists.” They might be scantily clad, but they were also highly capable and were more likely to be the rescuer than the rescued in any perilous situation. Nonetheless, Phillips signed her work L. Renee rather than with her first name. Phillips worked at Fiction House until 1948, then she and her then-husband, Eric Peters, both moved to St. John Publications, where Phillips drew the teen-girl strip Kitty and collaborated with her husband on Abbott and Costello comics.
By the early 1950s, Phillips had left comics more or less for good. She had divorced Peters and a few years later married Randolph Phillips, with whom she had two children. She wrote plays, illustrated children’s books, and did textile and jewelry design.
Robbins met Phillips in 2006 and included her in several of her comics history books; she also wrote a graphic novel, Lily Renee: Escape Artist, about Phillips' childhood. Phillips made several appearances at San Diego Comic-Con and was inducted into the Eisner Awards Hall of Fame in 2021.