company sergeant major 
noun
The highest-ranking non-commissioned officer of an infantry company.At the high school level, the first rank is recruit, followed by private, lance corporal, sergeant, staff sergeant and company sergeant major....
- Steve, who is in the Royal Artillery, was promoted from sergeant to staff sergeant while Tania, who was a company sergeant major in the Royal Logistics Corps, is now regimental sergeant major.
- One of the wreaths was laid by 90-year-old Chelsea Pensioner Martin McClane, a company sergeant major, who served with the 2nd Battalion Durham Light Infantry.