Coach Warren Gatland revealed his 37-man squad on Tuesday when, among the squad also containing 10 Englishmen, nine Irishmen and three Scots, there were several surprises for a three-test series marking the 125th anniversary of the first Lions tour.
The selection of Warburton was not one of them as the 24-year-old becomes the fourth Welshman to lead the Lions and the fifth-youngest captain.
The choice of New Zealand-born Scotland winger Sean Maitland, England prop Mako Vunipola and former England prop Matt Stevens, who retired from international rugby last year, did raise eyebrows in the packed hotel room as tour manager Andy Irvine read out the names.
There were only two flyhalves in the squad, Ireland's Jonathan Sexton and England's Owen Farrell, but three scrumhalves in Conor Murray, Mike Phillips and Ben Youngs.
While the halfback options might not have the Wallabies quaking, they will surely be impressed by the midfield and back- row power.
Brian O'Driscoll, the only survivor from the nail-biting 2001 Australia tour won 2-1 by the hosts, Manu Tuilagi and Welsh duo Jamie Roberts and Jonathan Davies are all daunting runners while the seven back-rowers provide a host of options.
Jonny Wilkinson, who ruled himself out of selection, England captain Chris Robshaw and Ireland hooker Rory Best were among the notable omissions.
"Yesterday was the seventh meeting we have had," Gatland told reporters. "We had probably 30 names settled but there was a robust debate about the rest.
"Some quality players have missed out but we feel we have an incredibly talented squad with great depth."
Having worked closely with Warburton as Welsh national coach it was widely expected that he would go with what he knew, despite the presence of vastly experienced former Ireland and Lions captains O'Driscoll and Paul O'Connell.
"We've got a good relationship but he's also been the most successful northern hemisphere captain over the last two years," Gatland said.
"He is an impressive individual and a natural leader. It's a fantastically strong squad but if I think about naming the team tomorrow, Sam would be one of the players in there."
Former Lion Neil Jenkins, on tour this year as kicking coach, said Warburton reminded him of Martin Johnson, who led the Lions to their last series win over South Africa in 1997.
"Like Johnno, he's not the biggest talker but he leads by example and has everyone's respect," Jenkins said.
Warburton was the only member of the party to know of his selection before Tuesday's announcement.
"It's been nine or 10 days since I found out and it's been the hardest secret I ever had to keep," said the man who led Wales to the Six Nations title this season.
"It's unbelievable, it's an accolade which very few people can achieve to be a Lion and the aim now is be a series-winning Lion, which is even rarer."
Another man who had to keep his lips sealed was defence coach Andy Farrell who lives with son Owen,
"I wanted to keep out of his way anyway on Sunday and Monday, he wasn't in the mood for talking," Farrell senior said following the 21-year-old Saracens flyhalf's semi-final defeat by Toulon.
That game, won 24-12 by the French side with all their points coming from Wilkinson, sparked widespread speculation that he would be included.
Gatland, however, said that the 33-year-old had ruled himself out due to his Toulon commitments and concerns over his fitness for a seven-week tour.
Stevens, who like Wilkinson had retired from the international game, was given a two-year ban from rugby in 2009 for cocaine use.
He returned and played in the 2011 World Cup squad but ended his 44-test international career last year.
"The tightheads we have are very similar and Matt can bring something different," said Gatland.
Maitland, a cousin of Australian back Quade Cooper, was an even bigger surprise having enjoyed a whirlwind seven months after uprooting from his native New Zealand to join Glasgow.
Within a handful of games he was called up to the Scotland squad and, having scored a try against England on debut and played all five matches in the tournament.
Gatland, who said he picked his fellow New Zealander for Waikato as a schoolboy, was impressed by his pedigree.
"He's a sub-11 seconds 100-metres man, he's a good footballer and makes good decisions in defence," he said.
"We've been impressed with what we saw in the Six Nations."
The powerful Vunipola, whose father Fe'ao captained Tonga, has started only one of his nine England tests but has proved to be a tremendous impact player, particularly in the loose.
The Lions kick off their tour against the Barbarians in Hong Kong on June 1 and will play three tests on June 22, 29 and July 6.
