42-year-old Jonathan Roman is charged with second-degree murder. He pleaded not guilty.
The judge ordered him held without bail, and remanded him to the Nassau County Jail pending a later court appearance.
Police say they found the body of 71-year-old John Frankowski of New Hyde Park buried in a wooded area behind Roman's home in Coram Friday.
Frankowski was reported missing last Saturday by his son, who lives in Florida.
Police believe an argument between Roman and Frankowski that escalated led to the murder.
The victim's son said his father was the greatest man he had ever known.
The son said his father was to have been the best man at his wedding in three weeks.