I'm still going with Johnny Majors. Overall record is 185–137–10.
Look at career record at each school
Iowa State 1969-1972
3-7
3-7
5-6
8-4
5-6-1
Pitt 1973 - 1976
6-5-1
7-4
8-4
12-0
Tennessee 1977-1992
4-7
5-5-1
7-5
5-6
8-4
6-5-1
9-3
7-4-1
9-1-2
7-5
10-2-1
5-6
11-1
9-2-2
9-3
5-3
Pitt (Again) 1993-1996
3-8
3-8
2-9
4-7
That's 11 losing seasons aout of 29
Not to mention he lost 4 or more games in a season 21 out of 29 times. Guys Johnny Majors is the worst coach to win a National Title.
That is a relatively poor career, but he was maintained as a head coach for a major program for 29 years.
Yet another reason I think Coker is a no-brainer (no pun intended) here is because he lasted 6 seasons in big boy ball, and will probably never coach a major program again. He finally got a job (after three years of nobody wanting him even as a coordinator) at a start up program, whose final three candidates were Coker, a co-defensive coordinator from Tulsa (not a program with a strong defensive record), and the HC at Northwest Missouri State. And, in all reality, they likely hired Coker primarily for his name recognition.
I could probably write a book justifying Coker as the worst championship coach ever. But, I think I have said previously, Chizik isn't out of the water by any means. He could compete with Coker, depending on the next few years. But, he will have to drive AU's program into the ground to compete with Coker. Again, Coker took the most talented program in modern history and made the program completely irrelevant within 6 years. His teams did not improve even once.