Rosenthal started his own accounting firm, Rosenthal Malloy, in 1929, after graduating from the University of Pennsylvania. His brother, S. Henry Rosenthal, had founded the firm of Goldenberg Rosenthal 10 years before. As each business grew, the brothers merged with yet another firm in 1968. Goldenberg Rosenthal has become one of the largest local certified public-accounting firms in the Delaware Valley.
Alex Rosenthal worked actively with clients until his 96th birthday.
In 1999, Goldenberg Rosenthal initiated the Alex Rosenthal Award in his honor. This award is presented annually to a member of the firm who "best exemplifies the outstanding qualities exhibited by Alex during a lifetime of achievement and client service."
Active in the community, Rosenthal served on the Finance and Budget Committee of Keneseth Israel and as a board member of Third Federal Savings Bank.
He also was active in the Allied Jewish Appeal and was a dedicated supporter of the Retired Senior Volunteer Program of Montgomery County for more than 15 years, having served on its board and chaired its finance committee.
One of his former partners remembers Rosenthal driving a truck for AARP to do tax returns for house-bound senior citizens.
In addition, he served as a trustee for several trusts after his retirement.
On the occasion of his 100th birthday, family and friends gathered to honor Rosenthal with a large celebration. At the event, he was presented with a proclamation from RSVP, thanking him for his years of volunteer service assisting low-income elders with tax preparation and providing the organization with wise counsel. He was also honored by the Pennsylvania Institute of Certified Public Accountants for his many years of service to the profession.
Rosenthal is survived by son Robert Alexander Rosenthal; grandchildren, great-grandchildren, nieces and nephews.
He was predeceased by his wife, Edythe Pincus Rosenthal; son Bernard Pories; daughter Doris Rosenthal Hagenbuch; sister Etta Kustin; and brothers S. Henry Rosenthal and Willard Rosenthal.
A memorial service will be held on Sunday, March 23, at 1 p.m., in the chapel at Keneseth Israel Reform Congregation, 8339 Old York Road, Elkins Park, PA 19027.
Memorial contributions can be sent to: The Richard Stockton College of New Jersey Holocaust Resource Center, P.O. Box 195, Pomona, N.J. 08240.