"There isn't any option for me," Miller said during a news conference at B.C. Place Stadium. "I wanted to make this move."
The Whitecaps acquired the Miller, who is the captain of the Scottish national team, from Cardiff of England's second-tier League Championship. Terms of the deal were not disclosed.
Miller said he had been contemplating a move to MLS for some time. The 32-year-old striker scored 11 goals in 50 games last season with Cardiff.
He joins a Vancouver side in need of offensive punch. Coach Martin Rennie, who also hails from Scotland, continues to look for more goals for his offensively-challenged club.
Miller became expendable in Cardiff after the Wales-based squad signed Slovenian international striker Etien Velikonja. Rennie said the Whitecaps were contacted by Miller's agents, and the striker indicated Cardiff helped arrange the deal.
Miller has 187 goals in 547 career club matches and is one of only five players after the Second World War to play for Glasgow rivals Rangers and Celtic.
The Whitecaps (8-6-6) have scored just 21 goals to date heading into Wednesday's home game against the Los Angeles Galaxy.
While Jamaican rookie striker Darren Mattocks has stood out with a club-leading six goals, Brazilian striker Camilo and French counterpart Eric Hassli have been inconsistent after ranking among league leaders with 12 and 10 goals, respectively, in 2011.
"We haven't scored quite as many goals as we would have liked," said Rennie. "So we wanted to get a little bit more proactive going forward. And when the opportunity came up to sign Kenny Miller, we really were excited to do it."
The coach hopes Miller can bring out the best in Mattocks and other young players. Rennie said the Edinburgh native can also provide leadership qualities that will aid the second-year club as it seeks a its first-ever playoff berth.
"He'll not only be a great addition on the field, but because of who he is and the character that he possesses, I think he'll be a great addition off the field," said Rennie.
Added Miller: "I hope I bring a little more than just goals to the team."
He becomes Vancouver's third designated player after Hassli and fellow Scottish international and friend Barry Robson. The Whitecaps created an opening for an international player last Wednesday when they sold midfielder Davide Chiumiento to Zurich FC of the Swiss Super League.
Rennie attributed the decision to move Chiumiento, who showed considerable vision on the pitch and factored into several recent goals with his adept passing, to the limitations of the MLS salary cap.
Miller's arrival marks Vancouver's third major transaction in less than a week. Vancouver traded Sebastien Le Toux to the New York Red Bulls on Friday for Jamaican midfielder Dane Richards and allocation money. Although Richards is classified as a midfielder he often moves forward.
But Rennie, who traded rarely used Chinese striker Long Tan to D.C. United in recent weeks, said he does not have a surplus of strikers. The Whitecaps could also make more moves before the current international transfer window closes.
"We are always building the squad with the long term in mind, and the window is still open," Rennie said. "If the right opportunity came along, we'd certainly look at it."
Miller will not play Wednesday. He has been training with Cardiff as it prepares for the start of its season, but has had limited activity since the Wales-based club's season ended in the spring.
"I think I will have a few games to take in before I have a better feeling as to how the game is actually played," said Miller.
Rennie predicted it won't take Miller long to get up to game fitness. He could be on the bench as a reserve when the Whitecaps host the San Jose Earthquakes on Sunday.
Notes: The Whitecaps released 300 more tickets Monday for the Galaxy game. But even with British icon David Beckham expected to play for L.A., the club will continue to limit seating to a maximum 21,000 in the lower bowl only. Lenarduzzi said the Whitecaps do not want to destroy the intimacy they have with their current arrangement. ... Rennie said an X-ray of Hassli's injured foot indicates there is no fracture. The striker was hurt while landing awkwardly following a header Saturday in Chicago.