Granted neither Jim nor John Harbaugh have been a head coach in the Super Bowl, however John has been a coach far longer than his brother, as Jim was too busy being a quarterback in college ranks and eventually and the NFL.
Jim was a quarterback coach for the Oakland Raiders for 2002-2003 then was named head coach of the University of San Diego Toreros in the FCS from 2004-2006. Jim did such a great job there that the Stanford University Cardinal offered him the coaching job in 2007 and he coached there until 2010 where he got offered the job with the San Francisco 49ers and as they say the rest is history.
As for John, he started his career for the Western Michigan University Broncos from 1984-1986 as running backs and linebackers coach. Then in 1987 he took over the tight end coaching reigns for the University of Pittsburgh Panthers and in 1988 he too over the special teams and defensive backs coach for the Morehead State Eagles. Then from 1989-1996, he was the special teams coach for the University of Cincinnati Bearcats and for a year in 1997 he coached the special teams and defensive backs for the Indiana University Hoosiers. From 1998-2007, John coached the Special Teams and corner backs with the Philadelphia Eagles and became a house hold name and ultimately became Brian Billick‘s replacement for the Baltimore Ravens and has been praised for his head coaching and leadership abilities.
While the brothers Harbaugh are both exemplary coaches to say the least, it just seems that John has paid his dues in the coaching realm far greater than Jim.