- "When I met your mom, she really knocked my socks off. Beautiful, blonde, tan… tight. Little did I know I’d be taking care of her schmuck kid forever."
- ―Sid to Johnny about Laura
He is played by Ed Asner.
Despite his wife, Laura, being a kind and caring mother for her son, Sid was a selfish and arrogant man who detested his step-son and berated whatever he was interested in. Sid also calls Johnny a social reject. Sid said that Johnny failed at drums and could not make use of a magic set, to which Laura pleaded to nurture Johnny's interest in the Cobra Kai Dojo, thinking it will help him make friends. Sid approved this on the basis this will be another example of wasted talent. Johnny ended up being dedicated to his lessons, ironically causing John Kreese to take a good deal of Sid's money with all those tuition fees.
Sid was verbally abusive to Johnny, saying that he would never amount to much and frequently calling him a "shithead". Laura died in January 2002, which changed his relationship with Johnny from a strained one into outright hostility. Johnny, in turn, realizes something Laura apparently never caught on to, that Sid never loved his mother nor valued her as a human being. Sid married Laura to have her as a trophy wife, and grudgingly raised Johnny as he had been her child from a previous marriage and refused to acknowledge him as his own. It's possible Sid abused Laura too and it's possible that he and Laura had an abusive relationship but that is unknown.
It's quite clear that Sid believes being nice never got a person anywhere and believes that some people are born as losers. He has been seen in the company of an African-American woman named Rhonda, who is his live-in nurse. Rhonda apparently does not enjoy the pleasure of Sid's company, only being near him as it is her duty and she is on his payroll. One time when Sid was groaning over a meal and the doorbell rang, Rhonda bluntly stated she is paid to be Sid's nurse, not his cook nor maid. It is revealed that Sid's disdain was not reserved solely for Johnny.
Despite detesting Johnny and never truly loving Laura, he did promise her that he would take care of Johnny, which he did by bailing him out of jail more than once, but eventually tried to buy him out of his life after he felt that Johnny was no longer worth it. However, after Johnny's newly reopened Cobra Kai became a success, Johnny returned all of Sid's money (money he gave Johnny to buy him out of his life) he used to re-open Cobra Kai and told him he would never see him again. At first, an arrogant Sid said he still needed him because of his money, only to be rebuffed by Johnny who told him he never needed his money, shocking Sid, and leaving him speechless. It is likely that Sid realized he could no longer bully Johnny or use money to control him, after Johnny gave back his money and walked out of his life for good.
When Johnny later visits him to ask for money to help with Miguel's surgery, Sid is still shown to be a cold and mean spirited human being that mocks Johnny. Johnny then gets angry and nearly makes a fist as he looks like he is about to attack Sid but Sid gets scared and tells him to ease it down. Then, Sid refuses to help him. He also doesn't care when Johnny threatens to speak about a public event with his secretary, as he doesn't care about his reputation. When Johnny leaves, he calls Sid a cold human being that doesn't deserve to live anymore.
Pre Cobra Kai
Sid Weinberg was born on November, 15 1929. Sid was an executive for Lorimar Television, which is now defunct. At Lorimar, Sid gained a reputation for abusing subordinates. At one point, Sid bragged about how he told his subordinates that he was the one "who runs Lorimar". This reputation stayed with him for the remainder of his life. Sid's work with Lorimar allowed him to be become wealthy, and he used his wealth to enjoy a fabulous house and memberships to country clubs. In 1967, Sid married Laura and became the stepfather to Johnny when the latter was a kid. Sid, however, disliked Johnny and constantly made a point to berate and bully him. When Johnny told Laura he wanted to take lessons at the Cobra Kai Dojo, Sid ridiculed him but ultimately decided to allow Johnny to take lessons after being persuaded by Laura.
After losing to Daniel in 1984 (which Sid undoubtedly rubbed in his face) and being disillusioned by Kreese and quitting Cobra Kai, Johnny was subjected to further verbal abuse from Sid, this time with no place to turn.
Following Laura's death in January 2002 (possibly), weeks before Robby's birth, his relationship with Johnny became even worse. The fact his loving mother was gone and the despicable Sid would live on for several more years caused Johnny even more bitterness, Sid kicked Johnny out of his house causing him to live in a decent apartment in the Reseda Flats.
Sid bails Johnny out of Jail, laments how much of a burden Johnny has been to him and gives him a check in an attempt to buy him out of his life. Johnny refuses and tears up the check, possibly remembering his rough childhood, when Sid emotionally abused him. However, when he re-opens up the Cobra Kai Dojo, Johnny tapes it together and cashes it to start the business.
After the Dojo becomes successful, Johnny recoups the money used to buy it, then returns to see Sid at his home. He gives Sid all of his money back that he used to open the dojo and tells Sid that he never intends to see him again after Sid claims that he "needs [his] money", saying: “I never needed your money. It’s just the only thing you had to give. Goodbye, Sid.”, leaving Sid to stun in disbelief as he can no longer use his money to control or show any kind of superiority towards Johnny anymore.
While he does not appear, Johnny has a flashback of himself as a teenager briefly crying to his sensei John Kreese about Sid.
Johnny arrives to Sid's house in request of some money to help fund Miguel's surgery. Sid mocks him for many reasons, believing he was a loser. Johnny then threatens to speak out to the public of a secret incident that Sid had with a secretary. After claiming that he didn't achieve financial success due to his reputation, he angrily tells Johnny to get out, in which Johnny does, but steals Sid's expensive souvenir on his way out in order to sell and pay for Miguel's surgery in payback for the way he treated Johnny. Rhonda has most likely quit being Sid's nurse due to his abuse and little respect for those around him.
Sid appears as a boss in the video game Cobra Kai: The Karate Kid Saga Continues.
It was unclear if Sid will make any further appearances initially, as it was assumed that Johnny would never contact with him completely, in which Johnny would then later visit him at his home to ask for help in order to pay for Miguel's surgery. Failing to do so however, this will most likely be Johnny's last encounter with him because of his superannuated age and Johnny needing no financial support after Miguel's surgery being paid.
- Sid's name is likely an obvious reference to Sid Sheinberg, who was president and CEO of MCA Inc. and Universal Studios for over 40 years. Like Sid Weinberg was the president of Lorimar Television, another entertainment company.