The soldiers were in the US on a military rugby team trip - which it is believed included playing a match against the NYPD - when the incident happened. The officer was punched and his mobile phone taken, according to reports.
All four serve in the Royal Scots Borderers, an infantry battalion of the Royal Regiment of Scotland.
Court records show Ratu-losefo Yavala pleaded guilty to misdemeanour assault and petit larceny - the theft of another person's property - while Thomas Shute admitted misdemeanour assault.
Mosese Kurulala and Iliakini Raderua pleaded guilty to violations, not crimes under US law.
Shute, who is British, was given a year's conditional discharge, ordered to carry out five days' community service and fined $500 (£314) at the New York Criminal Court.
The other three, who are all from Fiji, were sentenced to community service and fines.
A Ministry of Defence spokesman warned that those who fall short of Army standards face disciplinary action and could be discharged.