Speaking ahead of the 70th anniversary of her accession to the throne on 6 February, Justin Welby said she showed "duty, leadership and character".
He described her Christian faith as "the rock on which she stands".
On Sunday she becomes the first British monarch to mark a Platinum Jubilee.
In an interview with the BBC, the archbishop said the Queen had committed herself to a life of duty and public service.
"The clearest moment for me, the absolute summit of that, was that at the funeral of her husband of 70-something years, she sat alone.
"That was leadership, it was doing the right thing, it was duty, it set an example," said the archbishop, who officiated at the funeral, which observed Covid restrictions in place at the time.
The remarks are likely to be seen as adding to the comparisons with how Covid rules have been observed in Downing Street.
The government has faced intense pressure over events held in and around Downing Street during the pandemic, including two parties held by staff at No 10 on 16 April 2021, the night before Prince Philip's funeral.
Archbishop Welby said the Queen's long reign had provided an international symbol of stability through decades of social and political upheavals.
But he said that her own character was about "humility" and understatement.
"She takes her duties seriously, but she doesn't take herself very seriously. She laughs in private, she has an absolutely superb sense of humour," said the archbishop.
"'It's not about me' almost sums up her reign," he said.
The Queen, aged 95, had a "sense of self-acceptance", said the archbishop. "She doesn't question who or what she is."
The Archbishop of Canterbury emphasised the personal importance of religious faith to the Queen, since she took the throne after the death of King George VI, the father she "adored".
The archbishop likened her role as monarch to a lifelong religious vocation and the coronation to the vows for religious ministry.
"The coronation service is a form of ordination, in a liturgical sense, and she lives that out without a grumble."
"It is priestly - the language, the structure, it's very similar to an ordination of a priest or a bishop," he said.
The archbishop said the Queen had faced "intense grief", including the loss of her husband, but her personal thoughts remained closed.
"She's immensely private on such things. That is who she is," said the archbishop.
The Queen, the world's longest-serving head of state, is in Sandringham, Norfolk, for the anniversary of her accession in 1952.
It's also a poignant occasion, as this is where her father, King George VI, died, and in photographs published on Friday she is seen wearing jewellery that he gave her for her 18th birthday, in 1944.
Before leaving Windsor Castle she was shown well-wishers' cards and historic items from previous jubilees, including a fan signed by royal relatives from Queen Victoria's Golden Jubilee in 1887.
"It's very well preserved. Extraordinary, isn't it?" she said, holding up the fan, which included a signature from "Nicky", who became Tsar Nicholas II of Russia.
Queen Victoria had previously held the record for the longest reign in Britain, with more than 63 years on the throne.
Officials at Buckingham Palace say they expect 100,000 letters and cards from well-wishers to be sent to the Queen in a jubilee year.