Jules Eratosthenes Brown was the oldest son of Doc and Clara Brown. Jules was most likely born in 1886 or 1887. His first name was in reference to Jules Verne, the favorite novelist of his parents. His middle name was in reference to Eratosthenes of Cyrene.
Unlike his younger brother Verne, Jules was very smart for his age and took after his father in that he would use very long words in his everyday speech. He always called Marty McFly "Martin". Jules was top of the class at school, however he was not that popular and only had a few friends. Nevertheless, he was usually quite good natured, even if he did tease his brother quite a bit. Jules did once let being rich go to his head after he grew a money tree. He appeared to have a crush on his classmate Franny Philips and also liked baseball and inventing.
When Doc and Clara were left behind in 1885, they had no way of leaving the 19th century since the DeLorean time machine, with Marty inside it, had gone back to 1985 where it was destroyed by a train (Marty managed to escape in time). Doc and Clara married, and had their sons Jules in 1886 and Verne in 1888.
Doc knew that he shouldn't have remained in the past, and neither should his family, since Clara should have died in 1885 and Jules and Verne never existed originally. As such, he managed to build a new time machine out of a steam train and managed to get his family out of the 19th century and back to the 20th century. The family visited 1985 to see Marty and Jennifer, where Jules met them for the first time.
Jules, along with the rest of the family, moved to the 20th century. By 1991, when the series began, Jules appeared to be about 10 or 11 years old, biologically, consistent with being slightly older than when he left the 19th Century, paid a brief visit to 1985 in the time train, and then settled down with his parents in 1991 Hill Valley. (If Jules and Verne had moved permanently to Hill Valley in 1985, they would have been teenagers by 1991).
Jules once tried to become popular by inventing a money tree. Usually Jules would be with Verne (and sometimes his parents or Marty) in their time travel adventures. He invented a machine that would provide newspaper headlines from any day in history, which he later used to save his parents from a space cruise in 2091 that would end up crashing, and was indirectly involved in almost erasing electricity from existence (after saying to Verne that he was adopted, Verne thought Benjamin Franklin was his father and interfered with the famous kite experiment).
- Erhardt Brown: Paternal grandfather
- Sarah Lathrop-Brown: Paternal grandmother
- Daniel Clayton: Maternal grandfather
- Martha Clayton: Maternal grandmother
Behind the scenes
- The canonicity of the animated series as an extension of the films' storyline is unclear. In most of the fanon it has been accepted that the Brown family resettled in the 20th Century, thus allowing Clara and her children to live beyond their natural years. In the Video Game, Doc and Clara had decided to resettle in early 1986, which coincides with the Animated Series.
- Jules was born in 1886, more than 30 years before his time-travelling father, Doc Brown. After Doc created a new time machine in the 1890s, however, Jules and the rest of his family departed the 19th century. Otherwise, Jules would have been 36 years old by 1920, when Emmett Brown was born and deceased in 2015 aged 129.
- Jules and his brother Verne are only briefly mentioned by Doc in the Video Game. At Doc's point in life he mentions that their early teens and he and Clara were discussing what era in time they were going to send the boys to college in. Marty brings them up again when talking to Citizen Brown.
- Although the ages of Jules and Verne in the animated series are not stated, they attend elementary school. Actor Joshua Keeton was 12 years old when he voiced the role of Jules Brown in 1991.
- Back to the Future Part III
- Back to the Future: The Animated Series
- "A Family Vacation"
- "Forward to the Past"
- "Roman Holiday"
- "Go Fly a Kite"
- "Batter Up"
- "Solar Sailors"
- "Dickens of a Christmas"
- "Gone Fishin'"
- "Clara's Folks"
- "Put on Your Thinking Caps, Kids! It's Time for Mr. Wisdom!"
- "Bravelord and the Demon Monstrux"
- "The Money Tree"
- "My Pop's an Alien"
- "Super Doc"
- "St. Louis Blues"
- "Verne Hatches an Egg"
- Back to the Future (Harvey Comics)
- Back to the Future: The Game
- Back to the Future: The Game - Episode 1: It's About Time (Mentioned only)
- Back to the Future: The Game - Episode 3: Citizen Brown (Mentioned only)
- Back to the Future (IDW Publishing)
| The McFly Family|
Marty McFly | George McFly | Lorraine Baines McFly | Jennifer Parker | Seamus McFly | Maggie McFly
Dave McFly | Linda McFly | Martin McFly, Jr. | Marlene McFly | Arthur McFly
| The Brown Family|
Dr. Emmett "Doc" Brown | Clara Clayton Brown | Jules Brown | Verne Brown | Einstein
| The Tannen Family|
Biff Tannen | Buford Tannen | Griff Tannen | Irving "Kid" Tannen
| The Strickland Family|
James Strickland | Roger Strickland | Irene Strickland | Edna Strickland | Gerald Strickland
Match, Skinhead & 3-D | Goldie Wilson | Douglas J. Needles