Mark and Diana Jacoby joined Philip Colleck, Ltd. in 1980 and have run it as a family business since 1987.

Mark Jacoby earned his BA in Art History from Kenyon College, and undertook graduate studies at The University of Delaware and completed the Christie's Fine Arts Course in London. He served as President of the National Antique & Art Dealers Association of America from 1991 to 1994, and is presently the First Vice-President of their Board of Directors. Mark served as Chairman of the Winter Antiques Show Dealers Committee from 1998 to 2004. He has been a member of the English furniture vetting committees for both the Winter Antiques Show and the International Fine Art & Antique Dealers Show for the past nineteen years. Mark has been featured in the Wall Street Journal and the New York Times and is regularly quoted in trade magazines and journals.

Diana Jacoby earned her BA in Art History from Finch College in New York City and studied interior design at Parsons School of Design. Diana has served on the Board of Directors of The National Antique and Art Dealer's Association of America from 1998 to 2005. She has been quoted in the New York Times, Art & Auction, The Newtown Bee, The Antiques Trade Gazette and many other periodicals. In 2004, Diana founded Diana O. Jacoby Interiors, a design firm specializing in residential interiors.