Closeness to children and an optimistic view of change also helps sustain good heads, says Ronnie Woods, a National College for School Leadership researcher.
Previous research suggested that heads are at their peak after three years in the job, and often decline after 10 or 11 years to become forces for the status quo.
But Mr Woods, for 10 years head of Cleadon village junior school, South Tyneside, was interested in the characteristics of those with successful headships lasting 20 years or more.
He interviewed successful primary heads who have been in post since before the 1988 Education Reform Act. Most had trained in the 1960s and 1970s, the peak of child-centredness.
Many of these came from relatively humble backgrounds and were the first in their families to go into higher education - something that Mr Woods suggests helps form their humility and respect for others.
They were enthusiastic about children, teaching and learning, adapting national initiatives to suit their schools, and made frequent references to the support of "the team" (teachers, governors, parents). Some said government initiatives kept them on the ball.
"The reason we have kept enthusiastic is that there has been so much going on in education... you had to rise to the challenge or you would have gone under," said one.
See www.ncsl.org.ukresearchassociates (click on group 2) for full report