ɡɹˈædjuːˌeɪɾɪŋ ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti sˈɪks fɹʌm ɹˈɪŋɡəlɪŋ skˈuːl ʌv ˈɑːɹt ænd dɪzˈaɪn ɪn sˌæɹɐsˈoʊɾə, flˈɔːɹɪdə, mˈɑːɹʃəl bɪɡˈæn æz ɐn ˈɑːɹt dᵻɹˈɛktɚɹ æɾə bˈɪŋəmtən, nˈuː jˈɔːɹk, ˈædvɚtˌaɪzɪŋ ˈeɪdʒənsi, ᵻvˈɛntʃuːəli mˌeɪkɪŋ ðə lˈiːp æz ɐ fɹˈiːlæns ˈɪləstɹˌeɪɾɚ, wɪð ɐ klˈaɪənt lˈɪst ðæt ɪŋklˈuːdᵻd dʒˈɛnɚɹəl ᵻlˈɛktɹɪk, ˌaɪbˌiːˈɛm ænd ɡˈɑːlf daɪdʒˈɛst.
Graduating in 1976 from Ringling School of Art and Design in Sarasota, Florida, Marshall began as an art director at a Binghamton, New York, advertising agency, eventually making the leap as a freelance illustrator, with a client list that included General Electric, IBM and Golf Digest.