Roen was born on May 8, 1921, in Cleveland, Ohio.[1][2] He was awarded a baseball scholarship to attend Duke University, and graduated with a Bachelor of Science degree in Business in 1943.[1][2] He served as Lieutenant in the United States Navy from 1943 to 1946.[2]
Allard arrived in Las Vegas, Nevada, in 1949.[2] Shortly after, he was hired by Moe Dalitz to serve as the Managing Director of the Desert Inn.[1][2] As such, he negotiated with labor unions and construction companies to build the casino.[1] Shortly after it was built, in 1952, he added a golf course for guests.[2] When Dalitz acquired the Stardust Resort and Casino, Roen became its Managing Director as well.[1][2] In this capacity, he negotiated for the Le Lido, a Paris-based cabaret company, to perform at the Desert Inn.[1] A proponent of civil rights, he reached an agreement with the NAACP to allow black guests at the Desert Inn and the Stardust in 1960.[1] Eventually, he negotiated to sell the Desert Inn to Howard Hughes.[1]
With Moe Dalitz, Irwin Molasky and Merv Adelson, he founded Paradise Development, a real estate development company in the 1950s.[1] Together, they founded the Sunrise Hospital, The Boulevard Mall and the Las Vegas Country Club.[1] Roen served as the first president of the Nevada Resort Association.[1] He also served on the board of trustees of the Las Vegas Convention and Visitors Authority.[1]
In the late 1960s, he reconvened with Molasky and Adelson to develop the La Costa Resort and Spa in Carlsbad, California.[3] The luxury resort had a golf course and an equestrian center.[3] Roen served as its on-site manager from 1967 to 1987.[2] The resort was eventually sold to Sports Shinko Co., a Japanese company, in 1987.[1][2]
He was married to Evelyn Roen.[1][2] They had a son, Jeffrey, and three daughters, Judy, Priscilla, and Melissa.[1][2] Roen was one of the founders of the Jewish Federation of Las Vegas.[4]
He died of heart disease on August 28, 2008, in Carlsbad, California, at the age of eighty-seven.[1] His funeral took place at El Camino Memorial Park in San Diego, California.[1][2]