Oxford United chairman Ian Lenagan said the club had "thought long and hard about whether to employ a player with his [Luke McCormick's] background."
He added that McCormick's "clear repentance and the opportunity to allow him to rehabilitate whilst meeting our unique goalkeeping situation within the Salary Cap - which we might otherwise not have been able to do - resulted in our decision to sign him".
After his release from jail last summer, goalkeeper Luke McCormick was offered a trial at Swindon Town.
The mother of the two boys killed in the car crash said learning about the club's offer to McCormick was "like being hit in the stomach".
The goalkeeper was jailed for seven years and four months in 2008 for killing Arron Peak, 10, and brother Ben, eight, in a motorway car crash. He was twice over the drink-drive limit and speeding.
Amanda Peak, 34, whose husband Phil suffered a broken neck and back in the crash, told The Sun: "Swindon might be a family club, but now they're hiring a man who has torn my family apart."
Oxford United manager Chris Wilder said:
"We are very mindful of the past and the situation. Luke is very contrite and sorry about what happened.
"He was sentenced and went to prison and during that time had the opportunity to reflect on what he had done.
"It is hard to separate the two, but purely from a football perspective he is an experienced goalkeeper who has played most of his games in League One and the Championship.
"We have a situation here where our number one goalkeeper is out for the foreseeable future with a shoulder injury and we could lose Max Crocombe to International duty next month.
"We are offering Luke a chance to play again.
"I have spoken to Luke at length and he knows that it will not be easy for him but he is very humble and wants to try and make the most of the opportunity."
Oxford United have signed goalkeeper Luke McCormick, who was jailed in 2008 for causing death by dangerous driving.
The 29-year-old served half of his seven-year-and-four-month sentence he received after admitting causing the deaths of two brothers, aged 10 and eight, and driving with excess alcohol.
McCormick made 138 league appearances for Plymouth Argyle before he was jailed.
After release he signed for non-league Truro City and played 10 league games for the club before being acquired by Oxford.
A goalkeeper who killed two young brothers while he was drink-driving has been offered an opportunity to train with Swindon Town football club.
The club's interim chairman, Jeremy Wray, said Luke McCormick had been coming to the club on day-release since January and that once he is freed he will be training with the team but nothing more.
He said: "There is absolutely nothing more at this stage. People are getting ahead of themselves."
He added: "Luke is very contrite and full of remorse. He wants to give something back."
Swindon Town's interim chairman Jeremy Wray said Luke McCormick's move to the club was a chance for the goalkeeper to "give something back".
The mother of two children who were killed in a car crash caused by footballer Luke McCormick said it was "like being hit in the stomach" when she heard the goalkeeper would be joining Swindon Town this summer.