Urging voters to back Plaid in the May 2016 assembly election, the SNP leader praised Ms Wood for being modern, principled and passionate.
Ms Sturgeon said the leadership qualities of Ms Wood were proved in the general election TV debates.
She told Plaid's conference in Aberystwyth she knew Ms Wood would "stand firm" with the SNP against cuts.
Ms Sturgeon described the television debates as "filled with men whose only difference wasn't their politics, but the shade of their suit".
"Friends, in those debates Leanne Wood put forward a modern approach to politics - principled, passionate and prepared to lead Wales," she said.
"I was proud of Leanne, I know you were proud of Leanne and I promise you I will always work with Leanne Wood in the best interests of our two countries."
As her party aimed to win a third Scottish election in May, Ms Sturgeon said: "If the SNP can win in Scotland, there's no reason at all why Plaid Cymru can't also win in Wales.
"Not at some distant point in the future, but now, next May, at this election."
Plaid Cymru members in Aberystwyth enthusiastically applauded her endorsement of Ms Wood as a leader "of real star quality".
Ms Sturgeon also thanked Plaid Cymru for backing the 2014 referendum campaign for Scottish independence.
"I just hope that one day we will get to repay the favour," she said.

The men entered the Post Office in Quarrywood Avenue, in the Barmulloch area, at 07:55 on Friday.
They threatened a member of staff with a knife and demanded money before escaping with the cash.
The 27-year-old worker was said by police to have been badly shaken but otherwise unharmed by the ordeal.
Both suspects are white, and one of them was about 35-40 years old with short brown hair and wearing a black jumper.
Det Sgt Raymond Hunter said officers had been carrying out door-to-door inquiries and were in the process of collecting CCTV images from the surrounding area.
He added: "There are a number of other shops in this area and people may have seen the two men prior to or after the incident.
"I am therefore appealing to anyone who was in the area or any local residents to contact us - any information you have could assist our enquiry."

The environment department said anyone who injures, kills or disturbs Arctic Terns could face prosecution.
A spokesman said three walkers with dogs were seen "attacking" the birds with sticks and stones last weekend.
Biodiversity Officer Dr Richard Selman said: "Arctic terns will defend their nests and this can be painful."
He added: "Unfortunately, terns abandon their nests when the pressure from people or predators gets too great.
"They nest in a limited area and I hope people will respect the controls provided in order to give them the best chance of raising their young".
Arctic terns, which have the scientific name of Sterna paradisaea, have an average wingspan of 75-85cm.
The birds, which mate for life, lay one or two eggs in a small space of ground.
Scottish First Minister Nicola Sturgeon has said Plaid Cymru leader Leanne Wood is "ready and able" to lead Wales.
[NEXT_CONCEPT]
Two men have stolen a five-figure sum of money during an armed robbery at a Post Office in Glasgow.
[NEXT_CONCEPT]
An attack on nesting birds in a breeding colony in the north of the Isle of Man has prompted a warning from wildlife officials.