He was said to have been a prodigiously gifted child at the piano in his native Pittsburgh, where his school mates included pianist Errol Garner. He studied classical piano before turning to jazz. He was given the rather unflattering nickname of Dodo because of his large head and short body as a child.
His early inspirations were the great swing pianists Art Tatum and Teddy Wilson, and he made his professional debut at the age of 15 when he joined the Johnny Scat" Davis Orchestra in 1941. He worked with Gene Krupa and then Charlie Barnet in 1942-43, and made his first recordings with Barnet's big band.
While working with Krupa in 1943, he and clarinettist Buddy DeFranco were beaten up by a gang of sailors who mistakenly took them for draft dodgers. The incident is thought to have contributed to both his subsequent physical and mental ill-health.
It was during his tenure with Barnet that he first met Dizzy Gillespie, who in turn introduced him to Charlie Parker, the two key figures in the development of bebop.
He worked in succession for Tommy Dorsey (in a band which also featured Buddy Rich on drums) and Artie Shaw, and began to establish a reputation as a player of great technical facility as well as musical acumen.
Shaw remembered him as a gentle and fragile man who never really learned to cope with the pressures of jazz life, but he was also given to unpredictable behaviour. According to Barnet, he once pushed a piano off a balcony, and explained that he wanted to hear what chord it would sound when it landed.
After parting company with Shaw, he returned to Pittsburgh, then moved to Los Angeles, where he worked as a freelance. He recorded sides with Lester Young while with Shaw's band, and with Charlie Parker in Los Angeles, as well as working with eminent west coast musicians like Teddy Edwards, Howard McGhee and Wardell Gray.
He began to attract national attention in the influential jazz polls. His rich but fluent style was firmly rooted in swing, but incorporated the new harmonic and rhythmic discoveries of bebop, with its fast single line melody improvisations over spare left hand punctuations.
His health was not good, however, and he returned to Pittsburgh in 1948. Apart from brief tours with Scat Davis and Artie Shaw in 1949, he was only sporadically active in jazz for almost a decade, and most of that in low-key settings in Pittsburgh. A disastrous experience in the army in 1954 and the messy break-up of his marriage did nothing to improve his condition.
He recorded a new album, Dodo's Back, in Chicago in 1961, and two more sessions in 1962, with saxophonist Gene Ammons and trumpeter Bill Hardman, but it did not signal a long term return to the public arena. These were his last recordings, although he continued to play in low profile settings from time to time, the last of which apparently was at the Colony Restaurant in Pittsburgh in 1968.
In 1992, The Independent newspaper in London ran an obituary of the pianist, and The Guardian followed suit a few days later. It transpired that an English jazz enthusiast had been persistent in trying to contact Marmarosa for an interview. Eventually, the pianist himself answered one of his calls, and told him that Dodo Marmarosa had just died. The fan relayed the news to London, where it was passed on to writer Steve Voce, who published the news" a decade prematurely.
In recent years Marmarosa was resident in a medical centre in Pittsburgh, where he occasionally played piano and organ for other residents and guests.