One of the basic requirements of a hero is that they care about the well-being of others and is willing to put their body and life on the line to save others. Even though he has yet to meet anyone strong enough to put his life in danger Saitama rushes into battle without even considering any possible consequences that may befall him. In fact, Saitama's life as a hero began when he made the decision to save a kid's life from a Kaiju, despite the fact that it would almost definitely cost him his life.

In addition to risking his life for unknown citizens, Saitama has proven himself to be a great master to Genos. After taking Genos under his wing, Saitama has shown to care for him very much, often defeating opponents for turning him into a work of modern art.

The highest ranked heroes in the Hero Association are generally the most popular and well-known. At the bottom of C-Class heroes, Saitama is anything but well-known, and far from liked. But he's fine with that. Saitama joined the Hero Association because he wasn't recognized in the city or receiving credit for his heroic acts. Besides this smidgen of desire to be recognized, Saitama is content with not being the face of the Hero Association.

In fact, he willingly accepts the role of the most hated hero in the Association. Saitama consistently deals with high disaster level threats that threaten the city and single-handedly defeats higher ranked heroes. The quick rise in the rankings that this causes convinces other C and B rank heroes to believe that he is cheating and turns the people against him. Instead of fighting the allegations, Saitama admits to stealing the credit from other heroes, because he doesn't care what others think of him: He doesn't do the hero thing for admiration, he does it because he wants to.

Saitama's only concern about his image stems from insecurities regarding his training-induced baldness. In the episode "The Modern Ninja," Saitama seeks out Hammerhead and his gang to stop them from giving bald people a bad name and sullying his image. Also, his concern regarding the Hero Association is that he would receive the nickname "Caped Baldy." Don't mention anything about his baldness, and Saitama doesn't really care what you think about him.

When dealing with threats that endanger cities and even humanity itself, it's important to move with haste. When the situation calls for it, Saitama gets straight to work.

In the episode "The Ultimate Disciple," when an assortment of S-Rank heroes are unable to stop a meteor on its way to hitting City Z, all hope seems to be lost. Semi-fortunately for the citizens of City Z, Saitama knows that there's no time to mess around when lives are at stake. Seconds after appearing on the scene, he smashes the meteor (with one punch, of course).

Likewise, when the "Earth is doomed" prophecy seems to be coming true with arrival of Lord Boros and his spaceship, Saitama finds himself getting straight to business. Before anyone at the Hero Association HQ truly realizes that the threat is at their door, Saitama tunnels his way out of the building and makes his way to the ship. And while everyone –literally EVERYONE- is outside fighting Melzalgald and attempting to make their way to the ship, Saitama is making his towards Lord Boros, destroying the ship and taking care of Groribas and Geryuganshoop on his way.

In addition to his down-to-business attitude in fights, after defeating Crablante, Saitama decided to become a hero and didn't give up, no matter how hard things got.

100 push-ups, 100 sit-ups, 100 squats, and 10 km of running every day. Do that every day and you'll be as strong as Saitama. "How strong is Saitama?" you say. Well, let me tell you! For starters, there's a reason his show is called "One Punch Man." His punches are so strong that Saitama has created craters in the wake of his punches, turned a rainy clear, and parted the sky!

In addition to his signature technique of one-punching his opponents to defeat, Saitama has a slew of skills that show off his superhuman physicality. Saitama is shown to have lightning quick reflexes, super speed, a high level of endurance, and the ability to brush off the most devastating of hits. Saitama not only survived a hit that sent him to the Moon but was so unphased that he took a moment to reflect on his situation before jumping back to Earth - from the Moon.

Although he essentially fails the written part of the Hero Association's test, Saitama easily passes the physical test, shattering every previous record.

While heroes that take themselves and their jobs seriously are nice, it's also nice to have a hero that's able to enjoy the downtime. In battle and life. Saitama has found that right balance of being laid back and serious. When you're so strong that no one poses a threat to you it's easy to make your way through life with a carefree attitude.

When he's not out protecting City Z, Saitama is usually found lounging at home and idly passing his time. In fact, he lives out his life like any other regular person. Saitama usually doesn't exert himself unless there's a real threat. His carefree attitude nearly lost him his standing with Hero Association, as with no big threat he nearly went a week without meeting his quota of one good deed a week. In fact, this is the only time we see a stressed Saitama: as he rushes around the city looking for a good deed to perform.

Saitama even lets his carefree attitude carry over into his fights. Only getting truly serious when the time calls for it. During his fight with The House of Evolution's attack force, Saitama takes a moment of repose to enjoy the cool feeling of being in the ground, after being pulled underground by Ground Dragon.

Of course, as mentioned before, despite his overall laid-back and nonchalant attitude, Saitama knows how to get serious when the situation calls for it. Even if that situation his only as minor as missing a sale.