Just seven months after losing two top executives and three family members in a plane crash in New Jersey, Park Avenue financial firm Greenhill & Co. lost a junior associate as he was celebrating the start of his new career at Greenhill, The Post has learned.

Jack Roloson, 23, was hit by an SUV on the Garden State Parkway on Friday during an after-party celebration that went horribly wrong.

A memorial service was held yesterday in his hometown of Arlington, Tex.

Roloson moved to New York in June to join Greenhill after graduating from the University of Texas at Austin with a dual major in finance and molecular biology. His brother, Walt, had worked at Greenhill before joining hedge fund Tiger Global Management in 2008.