Mr Watt will join the small-cap specialist, best known for its team-based approach and the £1.2bn Smaller Companies trust, in April next year. The Edinburgh-based firm has also hired Kames Capital UK equity manager Peter Shaw, who will arrive in the same month.
The pair will replace Andy Bamford, a founding partner at Aberforth, who intends to retire at the end of 2015.
Mr Watt currently manages Jupiter’s Growth & Income, Responsible Income, and UK Alpha funds, which are £217m, £71m and £24m in size, respectively.
The fund house said responsibilities on Mr Watt’s portfolios will be reallocated during a “managed transition period”, with no changes to investment policies.
Environmental and sustainability team head Charlie Thomas will officially take over the Responsible Income fund when Mr Watt departs. Richard Curling, manager of the Jupiter Global Trust, Monthly Income fund and Fund of Investment Trusts, will take over UK Alpha.
The firm said it will reveal the new manager of the Growth & Income fund “in due course”.
Meanwhile, Mr Shaw’s departure from Kames has meant changes on the £282m UK Equity and the £66m UK Opportunities funds, which he co-managed.
Audrey Ryan has taken sole charge of the UK Opportunities fund, while Philip Howarth has joined Stephen Adams as support manager on UK Equity.