The 18-year-old signed for a $1 million bonus, MLB.com confirmed.
Greene, was selected No. 39 overall as a compensation-round pick, hit .562 with 11 doubles, one triple, 19 home runs, 52 RBIs, 58 runs scored and 13 stolen bases this season for Berrien County High School in Nashville, Ga. An outfielder listed at 6-foot-1 and 225 pounds, Greene earned a football scholarship to Alabama.
The Phillies also agreed to terms with second-rounder Roman Quinn, who was selected No. 66 overall, before Tuesday's 12:01 a.m. ET signing deadline. The 18-year-old switch-hitting shortstop batted .385 with a .510 on-base percentage, four home runs, three triples, four doubles, 21 RBIs, 39 runs scored and 20 stolen bases as a senior at Port St. Joe's High School in Florida.
The Phillies signed 30 of their 50 draftees, including nine of their first 10 selections.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.