Mackinnon Jacobs Lawyers originated in 1919 when Duncan Mackinnon established a practice after returning from Word War I. The firm, then known as Mackinnon & Colles and located in Queen Street, soon moved to new offices in Collins Street and became Duncan Mackinnon & Co. Although Duncan Mackinnon died in 1957, his name has been retained as an acknowledgment of his founding contribution to the firm.
In 1952, upon completion of his law course and return from World War II, Clifford Jacobs was invited into partnership with Duncan Mackinnon. In 1958, he established a branch office in Boronia and, in the mid-1960s, moved the city office to Richmond.
The Richmond office moved back to Collins Street Melbourne in 2006, then Queen Street Melbourne in 2009, then later to the current premises in Little Collins Street Melbourne in 2014.
Partnerships were accepted by Brian Irving in 1976 and Michael Jacobs in 1982 and, for a brief time, the firm was known as Mackinnon Jacobs & Irving. In 1983, the firm merged with Lew Horton & Co. and, with new partner Richard Horton, became Mackinnon Jacobs Horton & Irving Pty and later to Mackinnon Jacobs Horton & Irving Pty Ltd.
To meet increasing growth and demand, a third office was established at Rowville in 1997.
Partnership was accepted by Richard Kent in 2006.
Richard Horton retired from the partnership in 2007 but continued as a consultant to the firm until 2012.
Michael Jacobs retired from the partnership in 2018 but continues as a consultant to the firm.
Partnerships were accepted by Joseph Presutto and Anthony Presutto in 2018.
The firm currently trades under the name Mackinnon Jacobs Lawyers.
The firm is well placed to offer personalised attention to a wide range of legal concerns, and is well placed geographically, with the strategic positioning of its three offices.