Mullins is best known for his worship songs Awesome God and "Step by Step", both of which have been embraced as modern classics by many Christians. Some of his albums are also considered among Christian music's best, including ''Winds of Heaven, Stuff of Earth'' (1988), ''The World As Best As I Remember It, Volume One'' (1991) and ''A Liturgy, A Legacy, & A Ragamuffin Band'' (1993). His music has been covered by many artists, including Caedmon's Call, Five Iron Frenzy, Amy Grant, Carolyn Arends, Jars of Clay, Michael W. Smith, John Tesh, Chris Rice, Rebecca St. James, and Third Day.
Rich Mullins is also remembered for his devotion to the Christian faith. He was heavily influenced by St. Francis of Assisi (1181-1226). In 1997, he composed a musical called ''Canticle of the Plains'', a retelling of the life of St. Francis set in the Old West.