From: Amazing Spider-Man V.2 #61
Leo was a regular tailor, mending clothes and taking care of his grandson Mike after his son, who worked as a police officer, had been killed on duty. One day, the Thing walked in when his clothes had been burnt off by a fire-wielding villain, and he wanted to buy new ones.
Word quickly got around, and members of the Avengers, and later the X-Men started commissioning costumes.
Captain America once, after having taken a slash across the chest, but stating that “The important things come first” went to Leo before seeing a doctor. Leo considered it an honor.
One day Leo overhears one of his costumers, Killshot planning a murder over the phone, possibly the local District Attorney. Fearing that it will ruin his business and that Killshot might hurt his grandson in revenge, he does not go to the police. Mike pleads that his grandfather do something before someone dies, and Leo tells Spider-man everything when they meet each other on a late night walk.
Spider-man prevents Killshot from murdering the DA, but Killshot escapes and takes his revenge on Leo, shooting him in the arm before Spider-man rescues him and Mike. The DA tells the police to leave them alone when he realizes that Leo and Spider-man saved his life.
Leo later provides Robbie Baldwin, now Penance with a new armored costume. He is dismayed when Baldwin wants help putting on the suit, as its inside is covered in sharp spikes.