Martin (Marty) Hourihan was born into a middle-class Roman Catholic family in Tonawanda, New York in 1904. His mother hoped he would join the priesthood but at fifteen he ran away to San Francisco to become a seaman. During this period he became a member of the Industrial Workers of the World.

In 1921 Hourihan he joined the U.S. Army. He served for six years as a clerk until dishonorably discharged in Texas for what was called "radical tendencies". This involved writing bulletins that criticized the conditions at his camp.

Hourihan married a woman from Alabama in 1932. Two years later he participated in the Anniston Textile Strike. After his return to Alabama he tried to organize sharecroppers on his father-in-law's farm. This resulted in the breakdown of his marriage.

In 1935 Hourihan moved to New Orleans where he worked in the purser's department of several ships. The following year he took part in a large maritime strike along the Eastern seaboard. He was eventually arrested after a fight with blacklegs and spent twenty days in jail.

Hourihan, now a member of the American Communist Party, decided to fight for the Republicans in the Spanish Civil War. He joined the Abraham Lincoln Battalion and soon after arriving in Spain took part in the Battle of Jarama. Hourihan's commanding officer was Robert Merriman. When the battalion was ordered over the top they were backed by a pair of tanks from the Soviet Union. On the first day 20 men were killed and nearly 60 were wounded.

On 27th February 1937, Colonel Vladimir Copic, the Yugoslav commander of the Fifteenth Brigade, ordered Robert Merriman and his men to attack the Nationalist forces again at Jarama. As soon as he left the trenches Merriman was shot in the shoulder, cracking the bone in five places. Of the 263 men who went into action that day, only 150 survived. One soldier remarked afterwards: "The battalion was named after Abraham Lincoln because he, too, was assassinated." Edwin Rolfe survived but wrote: "When we were pulled out of the lines I felt very tired and lonely and guilty. Lonely because half of the battalion had been badly shot up. And guilty because I felt I didn't deserve to be alive now, with Arnold and Nick and Paul dead."

Hourihan was made the new commander of the Abraham Lincoln Battalion by a committee of the soldiers. In Comrades and Commissars: The Lincoln Battalion in the Spanish Civil War (2007) Cecil D. Eby claims that "Party hard-wires distrusted the new Lincoln commander, a political maverick so defiant of the Party line that at times he seemed not even to know what it was."

Jason Gurney, the brigade observer, was impressed by his new commanding officer. "Marty, in his role of Commander, inevitably lived a rather lonely life; he had to maintain absolute neutrality without any close friendships or favourites, but he was by nature a gregarious man and the friendship which we had formed for one another was very strong. He had a terrific sense of humour and, although he had little formal education, a very good mind and a superb sense of human sympathy. He never bore grudges or carried on feuds, he could be tough as hell in public, but there was much more of sorrow for human weakness than condemnation of wickedness in his outlook."

One of the first things Hourihan had to do was to deal with an accusation of incompetence against Oliver Law made by two veteran gunners, Ray Steele and Jim Katz. He was also accused of promoting friends to safer posts at headquarters and with "salting away catches of extra food for himself". Hourihan found Law guilty of the charges but he was overruled by a committee of political commissars.

Marty Hourihan became completely disillusioned by the actions of the Political Commissioners in the Spanish Civil War. His close friend, Jason Gurney, became convinced that Steve Nelson was "responsible for the mysterious disappearances of a number of people from among our ranks and for the secret trials, for real or imagined offences, which caused so much fear and suspicion within the Battalion." Gurney later recalled: " The nobility of the cause for which I had come to Spain was clearly a fiction, and now the sudden and absolute conviction that life was an experience with no past and no future, merely ending in annihilation."

Hourihan shared Gurney's feelings about the behaviour of the Political Commissioners who were taking their orders direct from the Soviet Union. On 5th April 1937 Vladimir Copic told Hourihan to leave their trenches to attack the Nationalist forces at Jarama. Hourihan refused and Copic replied: "You're cowards! You don't perform your duties! You're not aggressive enough!" Hourihan later told Steve Nelson: "I'm not going to give any orders to the Battalion to climb out of the trench and get themselves slaughtered until there is some real support." Gurney commented that Nelson and Copic accepted this because he knew "the entire Battalion was sufficiently angry to mutiny, as it had done before."

In June 1937 Hourihan joined Harry Haywood, Steve Nelson and Allan Johnson in demanding that Vladimir Copic should be removed as commander of the XVth Brigade. Copic wrote in his diary: "Hayward tells me that as a delegate of the Party it is his duty to tell me that the men have no confidence in the CO of the Brigade and want to replace me." Copic refused to go and threatened to arrest Haywood and his fellow rebels.

On 6th July 1937, the Popular Front government launched a major offensive in an attempt to relieve the threat to Madrid. The main battle took place at Brunete. Hourihan was given orders to capture the town. Oliver Law was ordered to reconnoiter the terrain the area in front of the town. He later discovered that Law had failed to do this and after denouncing him in front of the other men, he ordered him to report to Brigade. In the subsequent attack on the town Hourihan was hit in the leg by a sniper that resulted in his thigh bone being broken.

The medical board at Albacete ordered Hourihan to be repatriated as he was considered to be unfit for further military service. When he arrived back in the United States he resigned from the American Communist Party. As a result he was denounced by the Daily Worker as "an enemy of the working-class". Hourihan was also criticised for not having lost too many men during the attack on Nationalist forces on 27th February 1937. As the historian Cecil D. Eby pointed out, this was "proof for them that he had been more interested in saving lives (including his own) than in exterminating Fascists."

After the Second World War Hourihan obtained a teaching post in Greenlaw County. He also attended Huntingdon College, Alabama, graduating in 1959.

In 1967 Marty Hourihan was manager of a country club in Terra Haute, Indiana. The historian, Cecil D. Eby, who managed to find him later reported that: " Hourihan... made me promise never to divulge his whereabouts because he feared as a former Communist he would lose his job. To my surprise, he was not afraid of being denounced by the FBI but by the CP or VALB, as punishment for straying from the faith".