By Alexandra Ulmer

(Reuters) -Vivek Ramaswamy, a multi-millionaire former biotech executive, ended his White House bid on Monday and endorsed Donald Trump after his longshot bid caught attention but failed to catapult him high enough in the Republican Party's first nominating contest in Iowa.

Ramaswamy, a 38-year-old born in Ohio to immigrant parents from southern India, was one of the surprises of the 2024 Republican race dominated by former President Trump.

A fierce defender of Trump throughout the campaign, Ramaswamy likely secured himself a spot in Republican politics going forward with his youthful demeanor, deep pockets and fast-talking, pugnacious campaigning.

However, Trump turned on him in the final days leading up to the Iowa caucus, calling him a "fraud" and asserting that a vote for Ramaswamy was a vote for the "other side."

Still, Ramaswamy endorsed Trump on Monday, saying Trump was an "America-first" candidate who would have his full support.

"There is no path for me to be the next president," Ramaswamy told supporters in Des Moines after partial results from the Iowa caucus showed him in fourth place with around 7.7% of votes.

In his victory speech, Trump adopted a softer tone toward Ramaswamy. "I also want to congratulate Vivek, because he did a hell of a job," Trump said.

Harvard-educated Ramaswamy gained fame in right-wing circles thanks to his 2021 bestseller "Woke, Inc.," which decries decisions by some big companies to base business strategy around social justice and climate change concerns.

His combative debate performances and intense focus on media, especially social media, earned him headlines, but also put off some voters, and buzz around him ebbed in the autumn.

By the end of 2023, his national opinion polling numbers with likely Republican primary voters languished in the low single digits.

Ramaswamy's fellow Republican candidates often appeared irritated with the newcomer in debates, with former South Carolina Governor Nikki Haley telling him during one contentious encounter: "Every time I hear you, I feel a little bit dumber."

Ramaswamy says he was a libertarian while studying but has staked out some deeply conservative policy positions.

On the campaign trail, he opposed affirmative action and supported state-level bans on abortion after six weeks and said he wanted to greatly expand the powers of the presidency and dismantle much of the federal government, including the FBI and the Department of Education.

Ramaswamy was also reflective of a growing isolationist movement in the Republican Party, once made up of staunch foreign policy hawks. He opposed NATO membership for Ukraine and said Kyiv should make concessions to Russia to end the war, including allowing it to retain parts of Ukraine it occupies.