A pioneering Colorado senator who famously switched political parties and competed in the Olympics for the USA's judo team has died aged 92. 

Ben Nighthorse Campbell, who served two Senate terms - 12 years - beginning in 1993, passed away on Tuesday from natural causes, his family confirmed. 

The motorcycle-riding, cowboy boot-wearing politician was the first Native American to chair the Committee on Indian Affairs and the only indigenous senator during his tenure. 

The father of two was one of just four Native Americans elected to the chamber in US history. 

Campbell used his political platform to advocate for indigenous communities and children's rights, as well as to protect public land and defend organized labor.

While he undoubtedly had a vibrant and influential political career, Campbell - who also served three terms in the House of Representatives - was also an educator, athlete and US serviceman. 

Campbell was born in Auburn, California, in 1933. His mother, Mary Vierra, was a Portuguese immigrant and his father, Albert Campbell, was a member of the Northern Cheyenne tribe.  

He left high school to serve in the US Air Force from 1951 to 1956, earning his GED during that time, according to The Colorado Sun. He was stationed in Korea. 

Following his stint in the armed services, he attended San Jose State College in California, receiving a degree in physical education in 1957. 

In 1960, Campbell learned that judo would be included in the 1964 Tokyo Olympics - and was determined to compete. 

'I sold every damn thing I owned and I moved to Tokyo,' he once told The Colorado Sun. 

In Japan's capital city, he enrolled at Meiji University as a research student. He won a gold medal in judo at the Pan-American Games in São Paulo, Brazil, in 1963.

But he sustained an injury during the 1964 Olympics and did not place. He went on to coach the US National Judo Team.  

Upon returning to the States, Campbell taught PE at a California school district. The school asked him to teach a judo class for other staff members, which is how he met his wife, Linda, in 1966.

Falling quickly in love, the pair married just a few months later. They were together for 59 years and had a son, Colin, and a daughter, Shanan. 

Aside from martial arts, Campbell also loved jewelry making - a hobby that stemmed from his childhood. 

Campbell and his family moved to Ignacio, Colorado - a small town in La Plata County that is home to the Southern Ute Indian Tribe - in 1978. 

While raising champion show-ring quarter horses on their ranch, Campbell's jewelry-making career took off, earning multiple awards for his Native American-inspired designs. 

The Detroit News reported that he obtained a pilot's license and bought a single-engine plane so he could travel to jewelry shows around the nation. 

It was not until 1982 that Campbell seemingly stumbled into politics. 

While traveling for a jewelry competition, he was grounded in Durango, Colorado, due to poor weather. 

He met up with his friend at a Democratic Party meeting to pick a candidate to run for the House of Representatives. 

And when no one else volunteered, Campbell - who was no stranger to picking up a new skill - stepped up to the plate. 

'They asked, this guy said, "I’m busy," this one said, "I’m sick," that one said, "I can’t do it," so I wasn’t their best choice, I was the only one left,' Campbell recalled, per The Colorado Sun. 

That November, he ran with the party and won the election with 54 percent of the vote. 

Campbell was elected to the Senate in 1992 and changed his party to Republican in 1995 because he felt they were doing more for Native Americans. 

Reflecting on his career, Campbell said he was thrilled that as a senator, he was able to secure funding for police officers to wear bulletproof vests.

But above all, his proudest moment was getting the National Museum of the American Indian built on the National Mall.

'If I ever wanted to be remembered for one single thing above all others, it would be that museum,' he once told PBS. 

'Because I am a firm believer that you can’t have a good future unless you learn from the past.'

Campbell served as a senator until 2005. He announced his departure in 2004, citing health concerns - as he was battling prostate cancer - and a desire to spend more time with his loved ones. 

Post-Senate, he founded his own lobbying firm before finally retiring in Ignacio. 

After his death, loved ones and those who worked beside him shared glowing tributes to Campbell - who will be remembered as a bipartisan figure who valued honesty and integrity. 

In a statement from USA Judo, he was described as a 'steadfast advocate for Native American communities and a respected voice for Colorado on the national stage.

'Senator Campbell’s enduring legacy of independence, leadership, and commitment to others will be remembered with deep respect and gratitude.' 

'He was always generous to me with his time and wisdom. I will not forget his acts of kindness. He will be sorely missed,' Democratic Senator John Hickenlooper wrote on Facebook. 

'Ben was truly one of a kind - a man who lived not just one extraordinary life, but many,' former US representative Mary Bono said.