[1][3] After his 1979 ordination, the diocese assigned Walkowiak as pastoral vicar of Saint Mary Parish in Lorain, Ohio, where he would remain for the next four years.

[1] After Walkowiak returned to Cleveland in 1988, Bishop Anthony Michael Pilla appointed him as vice-chancellor and as a professor of canon law at Saint Mary Seminary.

[1] On April 18, 2013, Pope Francis accepted the resignation of Bishop Walter A. Hurley of the Diocese of Grand Rapids and appointed Walkowiak as his successor.

[1][3] Walkowiak released a statement on November 27, 2019, in which he supported the decision of Reverend Scott Nolan, pastor of St. Stephen Parish in East Grand Rapids, Michigan, to withhold the Eucharist from Sara Smolenski.

A town judge, Smolenski told the local media that Nolan notified her before mass that she could not receive communion because of her same-sex marriage.