McCroskey was a student of Brother Nels Thompson (who himself had been a student of Harry Ironside). Nels founded several assemblies, beginning in Oakland California. McCroskey succeeded him in these assemblies. More were added in Oregon and Arizona. McCroskey was an experienced printer, and in 1936 set up Gospel Tract Distributors to proclaim Paul’s Gospel. He became editor of the periodical Outside the Camp, which later became Last Day Messenger which remained in print until 1990.