Jeffrey "Jeff" Difford, usually called Pastor Jeff, is a pastor at the church Sheldon and his family attend in the series spinoff Young Sheldon. Sheldon considers Pastor Jeff an enemy of his and enjoys forcing Jeff to engage in lengthy debates over the credibility of Christianity.
Sheldon harbors anger towards Jeff for his pro-Christian principles and sermons, having gained multitudes of followers and refusing to allow even one atheist voice (Sheldon himself) to argue how science can contradict religion.
Pastor Jeff is a devout Christian who in his debut appearance declares the existence of God because it is cynical to doubt so. Sheldon, trying to fluster the pastor, claims there is a flaw in his reasoning and Jeff enthusiastically gives him a few seconds to elucidate, but then cuts Sheldon off short before Sheldon can talk any more about atheism and science towards the church. This is what makes Sheldon develop a strong contempt for Pastor Jeff and makes him more determined to discredit the pastor and his viewpoints.
Jeff was married to a Hispanic woman named Selena although she doesn't speak English, causing a language barrier between them. Selena doesn't seem to like Jeff and thinks he failed as a husband. Jeff stole Selena's own credit card for money behind her back because the church is losing money, thus putting Jeff and Selena at the risk of bankruptcy. Jeff tries to keep his financial hardship a secret from Selena fearing that this will make her want to divorce him. Also, Jeff lied or exaggerated to Selena how rich he is.
In S01E15, Sheldon claims that he still vows to destroy Pastor Jeff's comments about Christianity triumphing over atheism after having been denied the chance to do so using evidence of Earth's archeology and rock geology.
In A Math Emergency and Perky Palms, it turns out that Jeff's marriage with Selena has sunk so low that he tries to stay away from her as much as possible and stay outside his house even when he's sick with a flu.
As the series progresses, Jeff is depicted as being more concerned about how much money he can make off of promoting Christianity such as church attendance or church-related activities (such as a Halloween Hell House, which he uses to try to turn its visitors away from sinful behavior) instead of (or at least not only because of) sincere religious beliefs. That year, he had asked Mary Cooper to promote Hell House, which was done to resounding success.
Although he tries to pass himself off as a good, morally superb and reasonable person, Pastor Jeff on the inside is depicted by the show's writers as a greedy, insecure liar who will do anything to promote religion because the only way he can make money is to find more people in his town to convert to Christianity to the point where he tries to convert children. Jeff even tried stealing money from his wife Selena because the church is on the verge of bankruptcy. Jeff is an unskilled critical thinker. His decision to marry Selena was also a poor one, given that she was abusive and the two have nothing in common. However, despite this, Jeff is shown to be able to fluently speak Spanish when he translated Selena's language. Jeff was not financially prepared to marry Selena, yet he exaggerated to her about how well he's doing with money. She leaves him in the penultimate Season 2 episode "A Broken Heart and a Crock Monster", considering him a loser.
- Jeff, who appears to be a weak defender of his faith, tries (with mixed success) to discredit Sheldon's (and by extension, any atheist's) claims of there being "gaps" in the Bible and his attacks on Christianity's detailing of the origins of the universe. Making Pastor Jeff a weak and flawed defender of Christianity is by the design of series creator Chuck Lorre, who has a low opinion of religion in general and of Christianity in particular.
- Ironically, it is not Jeff who convinces Sheldon of God's existence, but Sheldon himself expresses his belief in the possibility of a higher power via scientific points he makes in "A Crisis of Faith and Octopus Aliens" as he attempts to help Mary through her crisis of faith and restore her faith in God following the death of a congregation member's teenage daughter in a car accident; he points out the precision of the universe, including gravity and electromagnetic forces being precisely as they are to support life as we know it, and rhetorically asks Mary what the odds are of these things happening by themselves. Sheldon then indicates that this logically points toward the existence of a Creator (which reflectively would actually make Sheldon an agnostic, not an atheist - which also indicates that Lorre dishonestly uses a broad definition of atheism to also include agnosticism in his depictions of Sheldon).
- His first name is Jeffrey, as revealed at his wedding to Robin in "A Live Chicken, a Fried Chicken and Holy Matrimony".
- Jeff becomes a hypocrite in Church. Thinking he is a man of god, but he is nothing but a fake.
|The Big Bang Theory Episodes|
|Young Sheldon Episodes|
|Appeared||M = Mentioned||Did not appear||Not aired/Not available|
|V = Voiced||C = Cameo||F = Flashback||I = Indirectly mentioned||P = Pictured|