One of the biggest financial supporters of Boston’s newest park, the Rose Fitzgerald Kennedy Greenway, is a New Yorker.

In its recently released annual report, the Greenway Conservancy, the park’s private operator, lists New York City Mayor Michael Bloomberg as one of eight donors who have contributed $1 million or more.

Bloomberg showed up at the official opening of the park a year ago and was later identified as the person whose contribution helped create the Mother’s Walk, a Greenway path dedicated to Rose Kennedy and lined with engraved bricks paid for by supporters. But the size of Bloomberg’s donation was never revealed, and his name never appeared as a donor on the Greenway Conservancy’s website. Instead, one donor was identified only as “anonymous.”

Stu Loeser, the mayor’s spokesman, said Bloomberg made the donation in honor of his mother, Charlotte Bloomberg, who still lives in Medford in the house Bloomberg grew up in.

Bloomberg, a self-made billionaire who founded the Bloomberg financial information firm, loves to give away money. In fact, he often quips that his goal is to give away all his billions so that when he dies, the check to his undertaker bounces.

In 2008, he donated $235 million to more than 1,200 organizations, making him the leading individual living donor in the United States, according to the Chronicle of Philanthropy.