He also played the voice of recurring character Francis Griffin in the animated series `` Family Guy '' . He appeared on the FX television series `` Rescue Me '' , playing Mike Gavin , the retired firefighter father of Denis Leary 's character .
Most recent television roles include the voice of Francis Griffin on `` Family Guy '' and Michael Gavin , the retired firefighter father of Denis Leary 's character , in the FX television series `` Rescue Me '' .