The review says since Mr Greenfield's arrival in 2012, school values and behavioural expectations have changed.
"Management systems have been improved and student support is better identified and coordinated," the review said.
Mr Greenfield said the most rewarding part of the review is that students and staff all agreed that it was a great school.
"Students express their pride in the inclusive culture of the school," the ERO said.
"They speak highly of the new principal and the opportunities they have to be involved in school activities and leadership."
The ERO suggested further monitoring of school leavers, to adjust the curriculum to reflect students' career options.
Mr Greenfield agreed that further data needed to be collected, and said the staff would be following through on this.
Kamo High School's last ERO review was in 2011 when it identified significant concerns about the schools management. The school roll was declining and there was a negative perception of the school in the community.
The ministry decided to put a limited statutory manager in to the school, to alleviate community concerns and the school leadership was changed.
Ex-principal Bernie Taffs unexpectedly resigned from his position before the 2012 academic year began.
Mr Greenfield expects the limited statutory manager to be removed from the school soon.