His first job was at a hotel in Lakewood, New Jersey. He worked there at the position of bellman, but he felt that this is not his destiny. Working in the hotel, he often saw comedians that traveled from city to city and entertained people. They inspired his and he decided to become a stand-up comedian. Since 1964, Gabe Kaplan has performed with his own funny stories. Most of the stories were built upon the situations that happened to him in Brooklyn when he was a child.

His favorite spot where he performed was Cafe Tel Aviv, New York City, but some time later he began to travel all around the country with his stand-up program. His attempts to become famous ultimately succeeded and he has been invited five times in the row as a guest to The Tonight Show Starring Johnny Carson (1973 – 1974).

In 1974, he released his own comedian album titled Holes and Mello-Rolls. Most of the content was his funny stories from his childhood.

From September 9, 1975, to May 17, 1979 he starred as the main character Gabe Kotter in an American television sitcom Welcome Back, Kotter, aired on ABC. Gabe Kaplan’s character was a high school teacher who struggled with remedial class. In this film, Along with Gabe Kaplan, debuted John Travolta. The series was quite successful, and on the money earned from it, Kaplan bought a gorgeous house in Palm Springs, California.

Gabe Kaplan liked to participate in different movies and TV shows, so from 1976 he appeared in Battle of the Network Stars on ABC and in the TV show Lewis & Clark on NBC.

When he left the series Welcome Back, Kotter, he decided to continue his favorite occupation – stand-up comedian. Then in 1979, he got the main role in an American comedy film, Fast Break. The feature of this film is his soundtrack "With You I'm Born Again", performed by Billy Preston. The song became so popular, that it reached #4 on the Billboard Hot 100 and then released on Motown Records label.

In 1978, Gabe Kaplan participated in World Series of Poker and in 1980 he won Amarillo Slim's Super Bowl of Poker, received the reputation of a professional poker player. From 1980 to 1985, he won this contest two more times and cemented his reputation as elite poker player. After that he won a lot of poker events including World Poker Tour, World Series of Poker, Poker After Dark, World Series of Poker in 2007, earned more than 1.3 million dollars in total. Therefore, his net worth now is about 30 million dollars.

There is no information about his family, children and wife, and even the trusted sources like Wikipedia or IMDb do not contain this.