Gruffydd was a traditional Welsh poet who wrote on religious and genealogical subjects in poems in the cywydd metre and songs in the free metre. Following the poets of the middle ages, he visited the homes of landed families to solicit their patronage and "return eulogy and elegy in time-honoured payment" (DNB). As the DNB explains, "This won him a reputation as a scholar–poet and antiquarian firmly in the tradition of the medieval bards... While not a fully professional poet, he was an important link in the interregnum between the demise of the poetic tradition and the neoclassical revival of the mid-eighteenth century." Most of his poems remain in MS form.