Marvin "Marv" Murchins was a burglar who regularly partnered with Harry Lyme, forming the "Wet Bandits", a name derived from their "calling card" of leaving their victims' water running and later, the "Sticky Bandits" after stealing money.
One evening while driving, Marv's partner, Harry, gloated about how the residents of the neighborhood informed him when they were going to leave for the holiday and that the McCallister house would be their prime target.
Marv and Harry attempted to break in during the day, but unknown to both of them, Kevin McCallister was still home. Kevin, after observing their shadows, turned on the lights, confusing the burglars and prompting them to flee.
While raiding the Murphy home, the phone rang and the answering machine came on with a message being left by Peter McCallister, giving the Murphys' the phone number to his brother's Paris apartment, confirming to the bandits that the McCallisters were gone and they planned to rob the house later that night.
On their way out, Marv left a 'calling card' by clogging the drains in the house and leaving the water running, much to Harry's disappointment. This led to an argument as they drive, but accidentally nearly ran over Kevin. Kevin recognized Harry, by his gold tooth flashing and fled. The two bandits becaue suspicious and followed Kevin, but lost track of him at a nearby church. Opting not to enter then church to search further, they fled, and Kevin (who was hiding in the nativity scene as a hooded shepard) returned home.
The two bandits later attempted to break in a second time, but as they went by, Kevin had the house lights on and the place appeared to be occupied due to mannequins that he was operating. Thus, the two assumed that the house was occupied, and decided to come back the next day.
When Marv came back the next day, he tried to break in through the dog door with his right foot, but ended up losing his shoe instead, which he quickly grabbed. Kevin, alarmed, turned on the Angels with Filthy Souls tape and set off a bunch of firecrackers, confusing Marv and causing him to wonder if there had been a murder at the place by other burglars. While Marv wanted to flee, the two opted to stick around and investigate further.
Later, the two saw Kevin trimming a tree from the yard and realize that he was home alone and decide to come back at 9 at night, which Kevin overheard.
That night, they began their planned plunder of the McCallister home. When Marv claimed he was Santa Claus, and "his elf", Kevin poked the BB gun out the doggy door, and shot Harry in the groin, causing him to squeal like a pig. When trying to enter through the kitchen, Marv stuck his head in through the doggy door, but was shot in the face by Kevin with a BB gun. As he went down to the basement, he slipped down a flight of frozen concrete stairs. He soon managed to enter and attempted to turn on a light, but only ended up with an iron falling on his face.
Then, he loses his shoes and socks while climbing tar-covered stairs on the basement and shoves Kevin's nail into his left foot after he steps on it, causing him to fall backwards and scream in inmense pain.
Marv left the basement and resorted to entering through a window, only to step on glass Christmas ornaments on the other side (making him scream with even more pain), angering him to the point of screaming out that he would kill Kevin. He finally reunited with Harry who had his share of traps and looked to Marv like a chicken, and they joined forces to capture Kevin. They chased the boy to a flight of stairs, but slipped on some toy cars Kevin had laid out. Then they attempted to go upstairs, but a swinging paint can hit Marv in the face, knocking him down. Harry was hit by one as well and landed on Marv. Marv remarked that Harry was "missing some teeth."
They got up and chased Kevin upstairs. Harry tripped over a wire and fell on his back, but Marv managed to avoid the trap and leapt at Kevin, managing to grab his foot. However, Kevin then placed a tarantula on Marv's face, causing him to let go of Kevin, scream, and fling it onto Harry's chest. Kevin ran upstairs while Marv grabbed a crowbar and attempted to smash the tarantula, only managing to hit Harry with it. Once Harry recovered, he angrily took the crowbar and hit Marv with it.
They continued the chase and followed Kevin, only to see he was already in a treehouse on the other side of the backyard. Marv reluctantly climbed the rope leading it, followed by Harry but Kevin brandished hedge trimmers and cut the rope, causing the bandits to fall to the ground. The two then manage to ambush Kevin at the Murphy home. As they threaten the boy, Kevin's neighbor Marley incapacitated them with a snow shovel.
While being arrested, Marv gloats about their crimes, thus confessing to a number of their burglaries. Harry kicks him in frustration, telling him to shut up as they are placed in the back of police car.
A year later, Marv and Harry escaped from prison and caught a ride on a fish truck to New York City. Putting double-sided tape on one glove, he stole money from a donation bucket and suggested to Harry that they adopt the name the "Sticky Bandits." which didn't impress Harry.
Later, Marv bumped into a fashion model and his hand accidentally stuck to her purse. After managing to pull his hand away, Marv said he was sorry in French, but the model did not accept his apology and slapped Marv across the face before leaving.
At an ice rink, Harry called Marv forth and acknowledged to him that they had to change their game, as they were not getting anywhere with stealing goods, deciding to steal cash instead. Marv suggested robbing hotels, but Harry knew that tourists were not guaranteed to have much cash. Harry pointed out that stores that specialized in moderately-priced goods would have the most cash in stock. When Marv suggested that the candy stores would have the most money on hand at Christmas time, Harry sneered that 'Nine year old's rob candy stores!' then suggested robbing a toy store, since they truly made the most money around Christmas time. Making it to Duncan's Toy Chest, they planned on staying there overnight, stealing the money, and then leaving the next morning.
Marv and Harry later saw that Kevin is also in New York and tried to catch him, but he used beads from a necklace in order to trip them up.
Marv and Harry later caught Kevin when he fled the Plaza Hotel after being exposed for having a stolen credit card by the staff. After ripping Kevin's plane ticket, so that he could not get back home to Chicago or Miami with his family, Marv revealed their entire robbery plan to Kevin and their plan to kill him, much to Harry's annoyance, with Kevin recording the whole discussion with his Talkboy. Kevin managed to flee their grasps once again when he caused Marv and Harry to be punched by the same woman that Marv had previously been slapped for hitting on earlier and escaped in the back of a horse-drawn carriage. Harry was initially discomforted knowing that Kevin is around, but Marv eased his worries, as Kevin had no home to booby trap them with, and on top of that, was now alone in Central Park, which nobody could survive at night.
On Christmas Eve, while Harry and Marv robbed Duncan's Toy Chest, Kevin knocked on the window, took a photo, and threw a brick through the window, setting off an alarm. Marv and Harry both unknowingly jumped onto a plank and trash can set up as a makeshift see-saw which sent Harry flying through the air and landing on top of a car.
They pursued Kevin to his uncle Rob's house. While attempting to bargain with the boy, Marv was hit four times by bricks that Kevin throws down, leaving him briefly disoriented. When Kevin left the roof, Marv went up the stairs and tried to open the front door, but was tricked by the knob which was attached to a staple gun via a rope on the other side. When Marv finally pulled on the rope, the staple gun fired into his buttocks. When he turned, the gun fired into his groin. He then fell and the gun fired again into his nose.
He then kicked the door open and, not noticing a gaping hole in the floor, fell down a three-story drop to the basement. He then got up and slipped in a puddle of soap, fell on his back, and crashed into an entire shelf holding tins of open paint, which fell on him. Now covered in different colors of paint, Marv went to the sink to try to clean himself up, he received an electric shock, briefly showing his skull.
Recovering, he found a rope placed conveniently for an exit out of the basement. However, the rope was attached to a bag of concrete, which fell on him. Eventually climbing out, he saw Harry on the ground with a cut-up ladder and they reunited. Going up the stairs, Kevin purposely tossed two paint cans down which missed. Laughing, thinking that had dodged a trap, they both went up the stairs only to be hit in the face with a metal pipe, which then fell on them after Kevin cut its ropes.
Later, they heard Kevin tormenting them and they pulled on a doorknob which came off and sent a toolbox down the stairs, opening the door and crashing into them. They made it on the roof and see Kevin an inch down from the roof. When Kevin taunts them of a neck injury, Marv picks up one of the bricks from which Kevin threw at him. Marv yells "suck brick, kid!" and throws the brick down at him, but he missed. When they climbed down a kerosene-soaked rope to catch Kevin, Kevin set it on fire and the burglars attempted to escape, only to fall several stories and get doused with varnish.
They soon caught Kevin after he slipped on a sidewalk and dragged him to Central Park to kill him. Upon seeing the trees full of pigeons, Marv became visibly uncomfortable, and wanted to flee, but Harry was too determined to finish off Kevin to care. The Pigeon Lady then appeared and threw a bucket full of birdseed on them, causing them to be swarmed by dozens of pigeons, deterring the bandits long enough for the police to arrive and re-arrest them.
The police found Kevin's photographs and recorded audio of Marv and Harry planning the toy store robbery. Gloating, Marv then revealed to the police that not only did they break into the toy store, but also escaped from prison. This infuriated Harry, who struck him multiple times to shut him up, but to no avail. As they were led away, Marv yelled out to remember that they were not the Wet Bandits anymore, but the Sticky Bandits instead, to which Harry yelled at Marv to shut up once more.
Despite both are very dumb, Marv is more of the muscle of the Wet Bandits. He's extremely dim-witted and while he has his moments of determination, deep down he is cowardly at heart. When something frightens him, he has a tendency to scream like a girl. He often under estimated Kevin, seeing him as just a stupid helpless kid who couldn't do anything, but he was twice proven wrong after falling victim to his many traps. In the first film, while he was initially repulsed at breaking into the McCallister home while Kevin was still inside, he became less sympathetic to the kid as he ended up bruised and battered from Kevin's traps. On two occasions when the traps get too agonizing, he declares that he will kill Kevin for scaring him mentally and physically. He is also a complete doormat to Harry and should he say anything stupid or haphazardly give the cops information Harry will respond by hitting him.
- Marv is played by Daniel Stern in the first two films. In the loose sequel Home Alone 4 (which shares a shoddy continuity with the original two movies), he is portrayed by French Stewart. For more information on the Home Alone 4 version of Marv see Marv Murchins (Home Alone 4).
- Daniel Stern criticized Home Alone 4 as being both an "insult" and "complete garbage", he refused to reprise his role for that film because of these reasons.
- Marv is canonically Jewish, considering the fact he said "Happy Hanukkah Marv!" to himself while robbing the toy store in Home Alone 2, Daniel Stern is also Jewish in real life, hence his character having the same feature.
- On December 24, 2015, Daniel Stern posted a video on his Facebook and YouTube channel, reprising his role as an older Marv pleading for Harry to help him as Kevin is back and targeting all home invaders in a sadistic manner, recalling their injures when they fell for Kevin's booby traps. Marv then hears someone approaching and the video cuts to black as the sound clip of Marv screaming when Kevin put Axl the tarantula on his face from Home Alone is heard.
- The video itself is a response to the DRYVRS episode that featured Macaulay Culkin reprising his role as an older Kevin and torturing a home invader (which, in actuality, was a carjacker.) 
- Murchins height is 6'4", being only a foot taller than his accomplice, Harry Lyme.
- Marv is a big fan of Nicolas Comics, he steals a stack of them in Home Alone.
- Robin Williams was originally considered for the role of Marv.