He was a 6'0" right-handed relief pitcher who played six seasons in the major leagues with the San Francisco Giants (1990, 1995–96), New York Mets (1992), and Pittsburgh Pirates (1993–94).Born in Grand Rapids, Dewey played for the Grand Valley State University Lakers.

[1] Dewey was involved in a notable controversy on July 28, 1996, when he refused to participate with his teammates in a pregame ceremony intended to support research of a cure for AIDS.

As part of "Until There's A Cure Day", members of the Giants wore AIDS awareness ribbons on their uniforms and stood in a group shaped like that symbol during speeches by Giants owner Peter Magowan and San Francisco Mayor Willie Brown.

Dewey refused to take the field for the ceremony, and he wore his ribbon sideways (which would have resembled the Icthys, a popular symbol meant to represent Jesus in Christian culture).

He cited religious reasons for his refusal, stating that the ceremony was "against [his] Christian principles" and voicing the belief that homosexuality is a sin.