David Bain has become a father for the first time.
His wife Liz Bain gave birth to a baby boy in Christchurch on Wednesday.
"Elizabeth and I are delighted to announce the arrival of our beautiful son. We are all delighted, happy, and in good health," Mr Bain said.
Long-time supporter Joe Karam said the birth was "a very satisfying reward" given his efforts over the past 20 years.
"I am delighted for David and Liz."
Mr Bain's mother-in-law Carolyn Davies refused to comment last night.
Mrs Bain, who goes by her family name of Miss Davies at Cotswold School in Christchurch, started a 12-month period of parental leave last month.
Teachers, staff and pupils sent their good wishes to the Year 6 teacher and Maori and Pasifika leader.
"Thank you Liz for the tremendous job you have done for the Cotswold family and we wish you and David all the very best as you look forward to starting your own family," a post in the school newsletter said.
In July, when news of the pregnancy broke in the media, Mr Bain spoke of the couple's delight.
"Our families and friends are extremely delighted for us and have been very supportive," Mr Bain said.
The pair, who met more than 10 years ago, married in front of 80 family and friends at Trent's Vineyard, on the outskirts of Christchurch, in January. They live in a small back-section flat, which Mrs Bain has owned since 2007, in the suburb of Redwood.
Mr Bain, 42, works at a local engineering firm. He was convicted in 1995 of murdering his Dunedin family and spent 13 years in jail before he was acquitted in a 2009 retrial.