After dropping out of the Football League in 2005, the East Anglians had twice lost in the Conference play-off final but confirmed their return by beating Gateshead at Wembley
The East Anglian club had twice lost in this fixture following their relegation from the Football League in 2005 but were all smiles after prevailing in a tense encounter at Wembley.
Richard Money's side finished second in the Conference behind champions Luton and overcame Halifax Town in the semi-finals, while third-placed Gateshead saw off Grimsby Town.
A cagey first half of the final ended goalless but Cambridge took control after the interval.
Liam Hughes nodded in a right-wing cross from former Gateshead man Ryan Donaldson to put Money's men ahead in the 51st minute.
A delightful free kick from Donaldson doubled Cambridge's lead 20 minutes later.
However, a nervy finish followed after Jack Lester pulled a goal back for Gateshead, with the North East club spurning a number of late chances to draw level.
Cambridge also had to cope with 10 men in the closing stages after Ian Miller was forced off through injury, with his side having made all three substitutions, but Gateshead could not capitalise.