Garth graduated with a bachelor of arts from Columbia University in 1942. He served during World War II as a United States Army Lieutenant from 1943 to 1946. Upon his return, he earned his law degree from Harvard Law School in 1952.
After building a private practice in Paterson, New Jersey, Garth was made a judge in the U.S. District Court for the District of New Jersey by President Richard M. Nixon in 1969, and elevated to the Third Circuit by Nixon in 1973. He assumed senior status in 1986.
Supreme Court Justice Samuel Alito clerked for Judge Garth from 1976 to 1977 in his first job out of law school. Judge Garth currently holds the distinction of being the only living judge for whom a member of the U.S. Supreme Court has clerked.
In his opening remarks before the Senate Judiciary Committee, Alito referred to his service with Garth as being formative, stating that Garth "taught all of his law clerks that every case has to be decided on an individual basis, and he really didn't have much use for any grand theories." Garth is said to disapprove of "results oriented" judging, instead holding that cases must be decided on the application of the law and legal principles, without reference to underlying social policy, or who among the litigants is more deserving.
Judge Garth is careful and strict about proper appellate procedure, and is the original author of the Circuit's internal manual for appellate jurisdiction and standards of review. The merits of a case can only be decided, in Garth's view, if the underlying procedure has been properly followed.
Garth's judicial philosophy, as Alito indicates, really isn't a philosophy regarding the law at all. It is much more a code of conduct for the proper execution of his duties as a judge. Garth believes strongly in giving every litigant's arguments his complete attention (his preparation for each case is legendary), making sure that any key factual points relied on by attorneys (or colleagues) are found in the record, deciding only so much as is required in order to resolve a case and not any more, and making sure that the decision is clear and unambiguous, so that it can be properly followed.