He was one of seventy applicants for the Middlesbrough job after Jack Robson departed and his record at Roker Park convinced the board that he was the man for the job, starting work in the summer of 1905. Following the football payments scandal at the end of 1905, he received a ban forbidding him from any active participation in football, unlike his predecessor who had the foresight to obtain a letter of absolution from the club chairman. However, Mackie was disillusioned with football by this point and so pre-empted the ban by voluntarily severing his interests.
He took over the Star and Garter Hotel in Marton Road, Middlesbrough in June 1906.