Former Florida Governor Jeb Bush has officially launched his US presidential campaign, promising to "run with heart" and "take nothing and no one for granted".
Mr Bush, the son and brother of two former presidents, spoke in his hometown of Miami, Florida.
Recently released campaign branding leaves behind his surname, which some see as a political liability, and polling suggests he has yet to dominate a wide field of Republican candidates.
The speech was preceded by a series of introductions and musical performances, with a strong Hispanic flare - an attempt at playing-up his connections to the Hispanic community.
In a video released prior the speech and played at the event before he spoke, Mr Bush pledged to protect the most vulnerable and remove barriers to social mobility.
In the video, titled The Greatest Century, he said: "I see a great country on the verge of its greatest century, and I'm ready to lead."
Although his campaign became official on Monday, it has been no secret for many months and his team is well on the way to raising a $US100m war chest.
During a tour of Europe last week, Mr Bush warned he would not waver from his core beliefs, even if some were unpopular in his party.
"I'm not going to change who I am," he said. "I respect people who may not agree with me, but I'm not going to change my views because today someone has a view that's different."
In a separate video, called Making A Difference, he champions the rights of women, ethnic minorities and the disabled.
"My core beliefs start with the premise that the most vulnerable in our society should be in the front of the line and not the back,'' he said.
"What we need is new leadership that takes conservative principles and applies them so that people can rise up."
A Spanish language video was also released, demonstrating his strong Hispanic links - his wife Columba is Mexican and he speaks Spanish well.
But in recent weeks he has found himself on the defensive over the Iraq War - led by his older brother, President George W Bush - as he stumbled to clarify his position.
The issue brought into focus the problems he may face over his famous surname and the baggage that comes with it.
He becomes the 11th Republican to declare, with Wisconsin Governor Scott Walker and Florida Senator Marco Rubio among his biggest rivals.
On the Democratic side, Hillary Clinton is the clear frontrunner. This raises the possibility in 2016 of another Clinton-Bush race like that of 1992, when Mrs Clinton's husband Bill beat Jeb Bush's father, President George HW Bush.
The declared presidential candidates
- Hillary Clinton, former First Lady and Secretary of State
- Martin O'Malley, former governor of Maryland and mayor of Baltimore
- Bernie Sanders, independent senator from Vermont, caucuses with the Democrats
- Lincoln Chafee, former senator and governor of Rhode Island
- Jeb Bush, former Florida Governor
- Ted Cruz, Texas senator and conservative firebrand
- Rick Santorum, Christian conservative from Pennsylvania
- Marco Rubio, Florida senator since 2011
- George Pataki, former three-term governor of New York
- Ben Carson, author and neurosurgeon
- Carly Fiorina, former boss of Hewlett Packard
- Mike Huckabee, former governor of Arkansas
- Rand Paul, libertarian conservative Kentucky senator
- Lindsey Graham, South Carolina senator since 2003
- Rick Perry, former Texas governor