Weddle is the son of a former Marine who fought in some of the bloodiest Pacific battles of World War II, such as Guadalcanal and Peleliu.
While Weddle was growing up, his family was close to several members of the renowned film director Sam Peckinpah's family, including his sister, Fern Lea (Peckinpah) and her husband Peter, and the director's son, Mathew Peckinpah. Later, through Matthew, Weddle met Sam Peckinpah and watched him direct some of his last movie, The Osterman Weekend.
Weddle graduated from the USC School of Cinema, as did writing partner Bradley Thompson, whom he originally met in an acting class.
After Sam Peckinpah's death, Weddle used the director's thousands of production files and personal correspondence in possession of the Motion Picture Academy Library, as well as his contacts with family and friends, to write a major biography of the director.
Weddle and Thompson first pitched stories for Star Trek: Deep Space Nine (DS9) at Paramount Pictures. DS9 Executive Producer Ira Steven Behr had read Weddle's book and Weddle secured an invitation to pitch for the show. Thompson & Weddle collaborated on pitch ideas for the series. Their first credited story on the series, was the fourth season episode "Rules of Engagement", which aired in 1996. The teleplay for the episode was written by Ronald D. Moore. Their first credited teleplay for Deep Space Nine was the fifth season episode, "The Assignment", which they wrote from a story by David R. Long & Robert Lederman in fall 1996. They co-wrote the later fifth season episode "Business as Usual".
They joined the DS9 writing staff as Story Editors for the sixth season in fall 1997. They wrote the episodes "Sons and Daughters", "One Little Ship", "Inquisition", "The Reckoning", and "Time's Orphan". They were promoted to Executive Story Editors for the seventh and final season in fall 1998. They wrote the teleplay for the episode "Treachery, Faith, and the Great River" from a story by Philip Kim. They wrote the episodes "Prodigal Daughter", "'Til Death Do Us Part", and "Extreme Measures". The latter two episodes were part of the tightly-plotted nine-episode arc that closed the series. The pair wrote for twelve episodes of DS9 across the series run. Also in the 1997 to 1998 season they wrote for the Fox series Ghost Stories. They scripted the episodes "Back Ward" and "Beware the Muse".
In fall 2000 they wrote for the short-lived drama The Fearing Mind. They scripted the episodes "Upgrades", "Call of the Wild", "Maximum Security" and "On the Road". The show starred Katee Sackhoff, who they would later write for on Battlestar Galactica.
In fall 2002 they wrote for the UPN revival of the science fiction anthology series The Twilight Zone. They wrote the episodes "Harsh Mistress" and "Fair Warning". They also wrote the story for the episode "Homecoming", which was developed in to a teleplay by Michael Angeli, who they would later write with on Battlestar Galactica.
DS9 producer Ronald D. Moore hired them for his new series Battlestar Galactica (BSG) in 2004. He invited them to a screening of the miniseries that launched the show in 2002. He then took them out to lunch to discuss ongoing storylines and invited them to join the writing staff. The show was a reboot of the 1980s drama of the same name for the SyFy network. Together with Thompson , Weddle served as a story editor on the first season of BSG. Thompson and Weddle wrote the first season episodes "Act of Contrition" and "The Hand of God".
Weddle and Thompson joined the production team as Co-Producers for the second season in summer 2005. They wrote the episodes "Scattered", "Valley of Darkness", "Flight of the Phoenix", "Scar", and "Downloaded".
They were promoted to Producers for the third season in summer 2006. They were writers and producers for the season bridging web series "Battlestar Galactica: The Resistance". They wrote the episodes "Exodus: Part 1" and "Exodus: Part 2". They remained in this role for the second half of the season in 2007 and wrote the episodes "Rapture" and "Maelstrom". They were made Supervising Producers for the feature length special Battlestar Galactica: Razor and the associated web series "Battlestar Galactica: Razor Flashbacks" in fall 2007.
They remained Supervising Producers and writers for the fourth and final season in 2008. They wrote the season premiere "He That Believeth in Me" and the mid-season finale "Revelations". The show took an extended hiatus after "Revelations" and resumed airing in 2009.
In fall 2008, Thompson and Weddle joined the staff of CSI: Las Vegas part way through the ninth season as writers and Supervising Producers. They joined the crew from the season's third episode "Art Imitates Life" onwards. They wrote the episode "The Grave Shift". They wrote the story for the episode "Kill Me if You Can", which was developed into a teleplay by Allen MacDonald. They wrote the teleplay for the episode "A Space Oddity" from a story by Naren Shankar. The episode focused on a murder at a science fiction convention.
They remained Supervising Producers and writers for the second part of the final season of BSG in 2009. They wrote the episodes "Sometimes a Great Notion" and "Someone to Watch Over Me". They wrote a total of 15 episodes for BSG.
In fall 2009, they became Co-Executive Producers and writers for the tenth season of CSI. They wrote the teleplay for the season premiere "Family Affair" from a story by Shankar. They also wrote the episodes "The Lost Girls" and "Irradiator".
In fall 2010 they returned as Co-Executive Producers and writers for the eleventh season. They wrote the episodes "Shock Waves", "Fracked", and "Targets of Obsession". "Shock Waves" and "Targets of Obsession" featured singer Justin Bieber in a guest starring role. "Fracked" won the Environmental Media Association's 21st Annual Environmental Media Award for Television Episodic Drama. They left the crew of CSI at the close of the eleventh season. They wrote nine episodes in total over three seasons.
During Falling SkiesEdit
In 2011, they joined the crew of the second season of the Steven Spielberg alien-invasion drama Falling Skies. They served as Co-Executive Producers and writers for the show. They took over the Co-Executive Producer role from their BSG colleague Mark Verheiden. The second season began airing in summer 2012. They wrote the episodes "Shall We Gather at the River", "Molon Labe", and the season finale "A More Perfect Union". Also in fall 2011 they served as Consulting Producers for the SyFy action series Alphas. They also wrote the story for the unaired pilot for the BSG prequel Battlestar Galactica: Blood and Chrome for SyFy, working with David Eick and Michael Taylor.