Williams was the arranger and pianist for recordings in Kansas City (1929) Chicago (1930), and New York City (1930). During a trip to Chicago, she recorded "Drag 'Em" and "Night Life" as piano solos. She used the name "Mary Lou" at the suggestion of Jack Kapp at Brunswick Records.Max Jones Jazz Talking: Profiles, Interviews, and Other Riffs on Jazz Musicians, Da Capo Press, 2000, p. 190; The records sold briskly, raising Williams to national prominence. Soon after the recording session she became Kirk's permanent second pianist, playing solo gigs and working as a freelance arranger for Earl Hines, Benny Goodman, and Tommy Dorsey. In 1937, she produced In the Groove (Brunswick), a collaboration with Dick Wilson, and Benny Goodman asked her to write a blues song for his band. The result was "Roll 'Em", a boogie-woogie piece based on the blues, which followed her successful "Camel Hop", named for Goodman's radio show sponsor, Camel cigarettes. Goodman tried to put Williams under contract to write for him exclusively, but she refused, preferring to freelance instead.Karin Pendle, American Women Composers, Routledge, 1997, p. 117;
