Friends and colleagues of the intiative, which opened to the public last year, used the occasion to celebrate its success.
The culture-led regeneration project has become a popular destination for residents and visitors to the Borders. It offers film, theatre, exhibitions, the first Beanscene coffee and music house in the Borders, and the archive and local history services of Heritage Hub. Local communities and businesses have welcomed and supported the facilities.
More than 100,000 visitors have visited the campus since the Heritage Hub opened in May 2007, followed by Tower Mill in September.
Councillor Zandra Elliot, Honorary Provost of Hawick, says it has been an exciting project which has breathed new life into Hawick.
"Its popularity is reflected in the numbers who have visited and I am sure it will go from strength to strength," she said. "Hawick and the whole of the Scottish Borders have another jewel in their crown."
Provost Elliot presented the 100,000th visitor, Pauline Dagg from Hawick, with her prize. The day's events also saw the installation of a 50-year time capsule under the glass floor in Tower Mill. This has been a collaboration between artist-in-residence Jane Gaze and more than 70 pupils from Hawick High School as part of the Heart of Hawick Junior Working Group.
Neil Mitchison, head of the European Commission office in Scotland, and Patrick Cadell, member of the Heritage Lottery Fund Committee for Scotland, played a leading role in the ceremony.
Borders fiddler and 2006 BBC Radio Scotland Young Traditional Musician of the Year Shona Mooney was also on hand in the Tower Mill auditorium playing from the distinctive Borders repertoire.
This included the tune Heart of Hawick, composed by Andrew Sherwood, professor of violin at Trinity College of Music, London.
By giving new life to the West End of the town, Heart of Hawick has achieved a number of key regeneration aims – a rundown area is now the focus of a social and cultural quarter linked directly to the High Street, key historic buildings have been restored and given visible uses, and the range of cultural activities now available are creating significant new employment opportunities and creative facilities for visitors and users alike.
Heart of Hawick won the Scottish Urban Regeneration Forum 2007 Award for best practice in urban regeneration in the category of Place as well as the Edinburgh Architectural Association Design Awards 2008 Medal for Regeneration/Conservation.
Tuesday's celebration was also an opportunity to recognise the significant capital investment in the project by Scottish Borders Council, the European Regional Development Fund and the Heritage Lottery Fund.
Heart of Hawick is a partnership principally funded by Scottish Borders Council, the European Regional Development Fund and the Heritage Lottery Fund.