Born on February 23, 2221, Michael Garibaldi had law enforcement in his blood. His grandmother was a Boston cop. Among other things, she taught Michael about the "blue flu" – calling in sick as an alternative to a strike.

Michael’s father, Alfredo Garibaldi, had worked in security all his life, even while serving under General Richard Franklin during the Dilgar war. He taught his son everything he knew. Alfredo Garibaldi used to say that laughter was better than pills for any ailment, and was known for "colourful" language. Every year, Alfredo would cook bagna cauda for Michael’s birthday as a present. After his father died of Torgs Syndrome, Michael started cooking bagna cauda for his own birthday as a tribute to Alfredo’s memory. Garibaldi believes that only real ingredients should be used in cooking, and refuses to substitute them with low-calorie or artificial products.

Around 2241, Michael started working as a security officer on the ice mining operation at Europa. It was a hard job, and corruption was widespread among the staff. Buckling under pressure, Garibaldi began drinking.

Things seemed to change when Garibaldi met Frank Kemmer, a pilot on the Jovian Moon Run. Garibaldi and Kemmer became close friends. In 2243, when Garibaldi was about to expose the corruption on Europa, the racketeers rigged a shuttle pad to explode - killing Frank Kemmer and framing Michael for his death. Unable to face Frank's family and blackballed by the security community, Garibaldi turned once again to alcohol for a "long, long time". His drinking problem became so severe that he once saw a chorus line of purple wombats doing showtunes in his bathroom. During these difficult years, he was fired from four security jobs.

After leaving Europa in 2244, Garibaldi worked on Orion 4 and Fortune City. He once had to use a shock stick to subdue a drunken prizefighter Walker Smith. Garibaldi and Smith became friends after that first awkward meeting.

During the Earth-Minbari war (2245-2248), Garibaldi served in the GROPOS. His wartime experience was terrifying enough to force him to see several counselors.

After the war, Michael ended up on Mars running a "no questions asked" shuttle service. In 2253, he was hired by a Lt. Comdr. Sinclair to take him and two junior officers to search for an "undisclosed" object. Sinclair never told Garibaldi what he was looking for, and Michael thought that the "war hero" was different from what he had expected. On the fifth day of the search, Garibaldi was forced to crash-land the ship. One of the JO's was killed, the other broke his leg, and Garibaldi and Sinclair had to hike 50 miles across the Martian desert to find shelter. During this journey, Sinclair and Garibaldi discovered two Shadow ships, as well as a top-secret Psi Corps facility on Syria Planum. Since that time on Mars, Garibaldi and Sinclair remained close friends. Michael would later recall this adventure in 2259 when Dr. Mary Kirkish visited the station.

Later in 2253, Garibaldi began to work as a member of Mars Colony security. It was in this capacity that he first heard of dust abuse in 2255. On Mars, Garibaldi started a serious relationship with Lise Hampton – they even talked of getting married. Around the same time, Michael met Jeffrey Sinclair’s girlfriend, Catherine Sakai, and began assembling an antique motorcycle – a ’92 Kawasaki Ninja ZX-11.

In 2256, Garibaldi was transferred to Babylon 5 on Commander Sinclair's request. He was quite surprised, since by that time he only met Sinclair twice. Garibaldi was well aware that the Commander’s choice of security chief wasn’t popular among members of Senate. However, he took the offer and left his drinking problem, as well as Lise Hampton, behind. Prior to the transfer to Babylon 5, Michael took his last vacation ever.

In January 2257, Garibaldi was wounded while chasing the Minbari assassin around the station.

In March 2258, Garibaldi discovered that Commander Susan Ivanova was using Gold Channel for unauthorized conversations with her dying father. Willing to bend the rules to accommodate her situation, Michael let this accident pass without consequences.

In the late spring, Garibaldi first met his nemesis, a Psi Cop named Alfred Bester, when the latter arrived to Babylon 5 on the Psi Corps business.

In the summer of 2258, presidential security officer Cutter framed Garibaldi for the explosion in Cobra Bay 11. Michael was exonerated when Major Lianna Kemmer exposed Cutter as a member of Homeguard. In his fight with Cutter, Garibaldi was stabbed.

In the fall of 2258, senior officers of Babylon 5 were interrogated by Colonel Ari Ben Zayn of Internal Investigations (II). Forced to assist Ben Zayn in his work, Garibaldi wondered aloud if Abbott and Costello now ran Earthforce. He also expressed his belief that sometimes you have to re-write the rulebook if you want things to work out.

Soon after, when the Mars riots broke out, an anxious Garibaldi made contact with Lise Hampton. Michael found out that she had married a man named Franz and was now expecting a child (later named Deborah).

In December 2258, Garibaldi uncovered a conspiracy to assassinate President Santiago and was shot by his own first officer Jack. Michael was later revived from a coma using the alien healing device, when Captain Sheridan and Dr. Franklin gave up a part of their life force to save his life.

Garibaldi didn’t return to work right away. Having been betrayed by Jack caused him to doubt his own professional qualities and even contemplate suicide. Only when the group of green Drazi kidnapped Commander Ivanova, Garibaldi realized that he was the right man for the job: he knew everything and everyone on the station, and didn’t trust anyone. On January 29, 2259, Michael resumed his duties as a security chief.

Seeing a new CO take the command of B5 didn’t change Garibaldi’s suspicious nature a bit. He even examined Captain Sheridan’s personnel file. Commander Sinclair left the station while Garibaldi was still in a coma. Only in March 2259, a Ranger delivered a confidential message to Garibaldi from Sinclair, in which the Chief was warned about the coming of a new warlike race - the Shadows.

In April 2259, the 365th Infantry Division arrived on Babylon 5 on their way to Akdor. Garibaldi met and was attracted to PFC Elizabeth "Dodger" Derman. Dodger, in her turn, thought that the Chief had a "nice butt" and offered him a no-strings-attached night of passion. Garibaldi declined her offer, still reeling from his breakup with Lise. He and Dodger agreed to get together later; sadly, she was killed on Akdor. In 2262, Michael was given a chance to see Dodger again during Brakiri celebration of the Day of the Dead. Dodger taught him that any poem by Emily Dickinson could be sung to the tune of "The Yellow Rose of Texas".

Garibaldi doesn’t believe in breaking the rules. He resigned as a chief of security when Captain Sheridan had jailed a survivor from the Icarus, a certain Mr. Morden, for no apparent reason. Only after an apology and an admission of guilt from Sheridan, did Garibaldi come back.

After the Narn homeworld was conquered by the Centauri in 2259, Garibaldi offered his help to the Narn ambassador G’Kar in smuggling arms.

In the spring of 2260, when G'Kar got high on dust and attacked the Centauri Ambassador Londo Mollari, Garibaldi put him in the brig. It was during this incarceration that Michael and G'Kar became good friends. G'Kar even gave Garibaldi his hand-written copy of the Book of G'Quan. (Garibaldi had to learn the Narn language in order to understand the book.)

Soon after, all members of Babylon 5 security were told to join Nightwatch or resign. Angered by this ultimatum, Garibaldi confronted representatives of Nightwatch On Babylon 5. His courageous actions helped several security guards to decide which side they were on.

In April 2260, Michael’s friendship with G’Kar came in handy when the ambassador agreed to reinforce Garibaldi's squad with Narns after Babylon 5 seceded from Earth Alliance, and its security force was purged of members of Nightwatch.

In May, while trying to replace the passwords in the station security system, Garibaldi accidentally revived Sparky - an old artificial-intelligence program with an attitude problem.

By August, having finished reading the Book of G’Quan, Michael realized that all Narn telepaths were exterminated by the Shadows who were afraid of telepaths. This discovery was instrumental in the eventual defeat of the Shadows.

On August 31, 2260, Jeffrey Sinclair returned to Babylon 5. Although Garibaldi was one of his closest friends, Ambassador Sinclair made sure that they didn’t meet this time around. When Sinclair took Babylon 4 a thousand years back into the past, he averted a "possible future", in which Garibaldi would have been killed on September 8 while defending Babylon 5 against the Shadow invasion.

In November 2260, Michael rediscovered Grey 17 and its strange inhabitants.

In December 2260, when Anna Sheridan came aboard, Garibaldi was asked by Sheridan to steal two nuclear bombs and smuggle them onto the White Star. He did as the Captain had ordered, knowing where he was going and having a good idea what he planned to do. On Boxing Day 2260, when Babylon 5 was attacked by the Shadows, Garibaldi was kidnapped and handed over to the Psi Corps.

At the top-secret facility on Syria Planum, Michael was programmed to become a pawn in Alfred Bester’s personal crusade against the mundanes. G'Kar went searching for Garibaldi and was subsequently captured. It was Zack Allen who eventually found Garibaldi on January 7, 2261.

After Michael recovered, he couldn't remember where he had been or what had happened to him. Everyone noticed that he seemed to be even more suspicious than before. Michael was tested for the evidence of Shadow implants in his brain, but the test came up negative. Garibaldi resigned from Earth Force in the spring of 2261 and began a career as a private investigator. His experience attracted a variety of clients, among them – William Edgars, a wealthy Mars industrialist.

In the summer, Michael was suddenly reunited with Lise Hampton when she visited Babylon 5. By this time, Lise had married Edgars after divorcing Franz and losing Deborah’s custody.

Garibaldi left Babylon 5 on September 2, intending never to return to the station again. He agreed to relocate to Mars (although, by his own admission, he hated the planet). Convinced by Edgars that President Clark will negotiate with the Mars resistance if Sheridan was captured, Garibaldi delivered Sheridan to the loyal forces.

Content that Garibaldi became a member of his "inner circle", William Edgars revealed his plan to infect all telepaths with a gene-specific virus. Only a vaccine supplied by Edgars Industries would keep the afflicted alive. Garibaldi informed Bester about this scheme. As a result, the headquarters of Edgars Industries was raided by Psi Corps, Edgars himself was killed, and Lise disappeared. Garibaldi was left alive by Bester – free to agonize over the magnitude of his betrayal.

In October 2261, Garibaldi attempted to contact the Mars resistance. He was captured, beaten and almost executed for treason. Only after a deep scan by Lyta Alexander, Garibaldi was exonerated and set free. He assisted Lyta and Stephen Franklin when they rescued Sheridan from prison. During the ensuing fight, Garibaldi was stabbed – yet again.

In November, Garibaldi found and rescued Lise Edgars who was kidnapped by the Mars Mafia. Michael returned to Babylon 5 just in time to throw a party for the newly married Sheridan and Delenn.

In January 2262, Garibaldi was introduced to the new commanding officer of Babylon 5 – Captain Elizabeth Lochley. The two became almost instant adversaries, after Lochley accused Garibaldi of putting his personal friendship with Sheridan before the interests of the station as a whole. After an assassination attempt against Sheridan, Garibaldi was made a new Chief of Covert Intelligence for the Interstellar Alliance.

Intrigued by the rumours that the new CO used to be a Clark loyalist, Michael accessed her personnel file. Garibaldi openly confronted Lochley later, claiming that Sheridan was forced into naming her as his successor. When the Psi Corps "bloodhounds" visited the station, Garibaldi was thrown in the brig after attacking Bester. During his incarceration, Garibaldi learned that Lochley and Sheridan were briefly married.

Michael was duped by Byron into allowing rogue telepaths to address the ambassadors of alien races aboard Babylon 5. This confrontation led to the beginning of the telepath war.

In the summer of 2262, Garibaldi was taken hostage by the besieged telepaths. The negotiations for his life failed when Sheridan refused to accept the ultimatum.

In 2762, long after his death, Garibaldi was "resurrected" by InfoSpeak division along with Sheridan, Delenn and Franklin. He managed to foil the attempt to use their images to destroy the Interstellar Alliance.

Garibaldi has revealed that he doesn't trust telepaths. Besides Sinclair, his close friends include Sheridan, Ivanova, Franklin, and Ambassador Londo Mollari. Garibaldi likes tea (his third favourite thing in the universe), Daffy Duck (Duck Dodgers in the 24 1/2 century is his second favourite thing in the whole universe), and Italian food. He is a pessimist and a perfectionist. He never starts a conversation without knowing the outcome. Garibaldi would love to be bored out of his skull for just 24 hours; he also likes quiet. His security access password is "Peek-a-boo". He usually fastens, then zips his trousers in the morning.