Frost was born into an observant Jewish family in the United States. He has two elder brothers, who are 15 and 16 years older than him respectively. Both brothers fought in World War II, one in the Air Force and one in the Army. At 13, he got his first job, working in a local hardware shop after school. Frost earned a B.A. in French literature from the University of Pennsylvania, in 1957. He received an M.D. degree from the Albert Einstein College of Medicine, in 1961 and attended the University of Paris, from 1955 to 1956.

He served as a lieutenant commander, U.S. Public Health Service at the National Cancer Institute, from 1963 to 1965. Frost was a professor of dermatology at the University of Miami School of Medicine, from 1966 to 1972. He was chairman of the department of dermatology at Mt. Sinai Medical Center of Greater Miami, Miami Beach, Florida, from 1972 to 1990.

Michael Jaharis and Frost bought Key Pharmaceuticals, Inc. in 1972. Frost was chairman of the board of Directors of Key Pharmaceuticals, from 1972, until its acquisition by Schering-Plough in 1986, for $835 million. Frost's share was $100 million. Frost's estimated net worth in 1986 was $150 million.

Frost served as chairman of the board of Directors and chief executive officer of Ivax Corporation, since 1987. He sold this Miami pharmaceutical maker, Ivax, for $7.4 billion, to Israel-based Teva Pharmaceuticals, in January 2006.

In October 16, 2003, a $33 million gift to the School of Music was announced by the University of Miami. In honor of their bequest, the largest ever given to a university-based music school in the U.S. at the time, the School of Music was officially renamed the Phillip and Patricia Frost School of Music. In 2003, the Art Museum at Florida International University was officially renamed The Patricia & Phillip Frost Art Museum. On March 26, 2011, it was announced that Frost had donated $35 million towards the construction of the new Miami Science Museum building at Bicentennial Park in Downtown Miami, named the Phillip and Patricia Frost Museum of Science. In March 2015, he donated an additional $10 million to support the development of the science museums' planetarium, the Frost Planetarium.

Frost became vice chairman of Teva Pharmaceutical Industries in January 2006, when Teva acquired Ivax Corporation. He was named the chairman of the board of Teva, in March 2010 and was reelected to the position in May 2012 before stepping down in 2015.

Frost became the CEO and chairman of OPKO Health, Inc. upon the consummation of the merger of Acuity Pharmaceuticals Inc., Froptix Corporation and eXegenics, Inc., on March 27, 2007. He was named chairman of the board of Ladenburg Thalmann Financial Services, an investment banking, asset management, and securities brokerage firm, providing services through its principal operating subsidiary, Ladenburg Thalmann & Co. Inc., in July 2006; and has been a Director of Ladenburg Thalmann, since March 2005. Frost also serves as chairman of the board of Directors of PROLOR Biotech, Inc. (NYSE Amex: PBTH), a development stage biopharmaceutical company.

Frost owns ~19% of ChromaDex, a publicly traded natural products company based in Irvine, California. In 2011, Frost became the largest shareholder in the Coconut Grove Bank, the oldest bank in South Florida.

As of December 2014, Frost serves on the board of Directors and is a 10% owner of Cocrystal Pharma, Inc., which was formed from a merger of BioZone Pharmaceuticals, Inc. and Cocrystal Discovery Inc. This company has also recently released news of a merger with RFS Pharma, adding even more expertise to the company focusing on advanced antiviral development.

A new set of STEM institutes was announced on January 23,2017 by University of Miami President Julio Frenk to be housed under the Frost Institutes name at the 50th annual Miami Winter Symposium held at the Hyatt Regency in downtown Miami, a prestigious event that attracted more than 100 Scientists, researchers and doctors from 28 countries. This transformational initiative is made possible thanks to the extraordinary $100 million gift by Dr. Phillip and Patricia Frost announced during Frenk's inauguration last year to support basic and applied sciences and engineering. A portion of the $100 million gift will be used for the construction of an iconic, modern science and engineering building on the University's Coral Gables campus, to be named the Phillip and Patricia Frost Science and Engineering Building. Of the gift, $30 million is designated to the creation of at least 13 chairs in STEM fields, with $3 million set aside for graduate student support.