Larry Mullen, Jr., was born on October 31, 1961, in Dublin. He was two years behind Bono in high school but both noticed each other. It was Larry who posted an ad on a bulletin board at school looking for musicians to start a band. Paul Hewson (aka Bono) was born on the 10th of May, 1960, in Dublin. He was a very outgoing person in high school who responded to Larry's note saying that he could play guitar and sing. He really couldn't do either. Adam Clayton was born in Oxfordshire, England, on March 13, 1960, and moved to Dublin after his father got a job flying for Aer Lingus. Although he was not a very good student, he was always very polite to everyone. He was the only bassist to respond to Larry's note. Dave Evans (aka The Edge) was born on August 8, 1961, in East London. His family moved to Dublin a year later. He was often known as a loner early in high school. He took piano and guitar lessons and often played with his brother, Dick. Both showed up to "U2's" first little gathering at Larry's house (60 Rosemount Avenue in Dublin). They set up in the Mullens' kitchen and played the Rolling Stones "Brown Sugar" and "Satisfaction." At this point, the entire group of hopefuls for the band included Larry, Dave and Dick Evans, Adam Clayton, Paul Hewson, and Ivan McCormick .

Bono, which is a shortened version of Bono Vox, his original nickname, got the name through a group of friends who were known as the Lypton Village. The name, which means "good voice" in Latin, was taken from the name of a hearing aid shop in Dublin.

Some reports say Edge was named by Bono because Dave was always on the fringe of things. Other stories suggest Bono gave him the name because of the sharp lines and angles of his face when he was a teenager.

In Lypton Village they thought it strange that you should go by a name given to you by your parents, when that name might not really suit you. The nicknames were often associated with a facial thing and it would then also apply to the person's character. So The Edge had this prominent jaw line & was always on the edge of things: like an observer. Bono's first Village name was: Steinhegvanhuysenolegbangbangbangbang. (!) Paul McGuinness became known as "The Goose." [SL, CB, GB, M2]
In the band's very early beginnings, circa 1978, Adam Clayton asked Steve Averill (formerly known as Steve Rapid of the band Radiators From Space) to help the band come up with a good name. Averill was interviewed by Hot Press magazine in 2001 and gave this answer when asked about how he helped U2 choose the band's name:

"When I first met them they didn't really know what they wanted to do, what type of band they really wanted to be. But they had qualified for the final of that band competition in Limerick and they needed to decide on a name. Adam liked names like XTC, which were short and crisp and could mean a lot or mean very little. So I made a list of ten and I put U2 on the bottom. I thought it was strong graphically and it had a variety of connotations without meaning something specific. It was short and stood out from the band names common at the time. After we discussed the list we decided to go for U2 for all those reasons."

There have also been many stories told about how the band's name is taken from the U-2 spy plane, and those stories gained favor with the connection of the famous Francis Gary Powers U-2 incident which occurred on May 1, 1960, and the fact that Bono was born just nine days later. These stories seem to be a stretch at best, and Averill's answer above makes no mention of the spy plane connection.

Averill, it should be noted, didn't stop helping U2 when he helped choose the name. He was also asked to manage U2 but declined, opting instead to handle U2's visual aspects. Averill and his partners at Four 5 One (formerly Works Associates / ABA) in Dublin also design U2 album covers, t-shirts, backstage passes, tour programmes, and even the symbols on Edge's hats during the Zoo TV Tour