He was joined at the unveiling event by Cllr Kirsten Hearn, Cabinet Member responsible for Parks, and artist Rachael Champion, who has created a locally-inspired sculpture for the new public space - which officially opens to the public on Monday 23 November.
Alongside the artwork, Hornsey Park features a new play area, with plenty of equipment and seating for local families to enjoy.
St William, the joint venture between Berkeley Group and National Grid, has also enlisted the help of local children to bring the site to life. Drawings from St Mary's Church of England Primary School pupils have been installed across the temporary hoarding, while the wider development works continue.
Cllr Adam Jogee, The Mayor, said: "It was an honour to officially open Hornsey Park - Haringey has some beautiful green open spaces and I'm thrilled we can add another one to our list. From boosting biodiversity to adding play equipment and brilliant artwork, I'm sure this is a place that local families will enjoy."
Cllr Charles Adje, Haringey Council's Cabinet Member for Finance and Strategic Regeneration, said: "The Clarendon project delivers for Haringey in a big way, offering as it does affordable housing, economic investment into the Wood Green area, local jobs and apprenticeships for our residents and impressive community amenities such as this fantastic park. I'd like to thank Rachael and the St Mary's Primary School pupils for their artistic contributions to this new park. They've really added a distinct local flavour to the overall scene that I believe our residents and visitors to the borough will truly appreciate and enjoy."
Sean Ellis, Chairman of St William, said: "We're thrilled to bring more public green space to Haringey, on what was once disused industrial land. Clarendon has been designed to boost biodiversity and help people connect with nature - we hope that the community will enjoy the park and that the new sculpture helps them to discover more about the local area."
Clarendon will provide more than 1,700 mixed-tenure homes, commercial space, and five acres of new publically accessible space. 250 trees, native species, seasonal planting and habitats for birds have all been included in the landscaping vision, to maximise nature on the site - with a 71% biodiversity net gain projected when works are complete.