 Following the resignation of Bishop Joseph M. McShea, Welsh was appointed the second Bishop of Allentown in his native Pennsylvania by Pope John Paul II on February 3, 1983.His installation took place at the Cathedral of St. Catharine of Siena on March 21 of that year.During his tenure, he established a "Stand Up For Life" campaign to encourage anti-abortion efforts, and frequently joined local abortion protesters for their monthly vigil at the Allentown Women's Clinic in Hanover Township.