The Be Wiser Ducati rider stole the lead of the opening race of the day at Brands Hatch at Surtees with two laps to go before the race had a premature end due to changing conditions.
At the start of the race Luke Mossey had fired the JG Speedfit Kawasaki off the line to take the lead from pole sitter Josh Brookes and Linfoot. However a hectic opening few laps saw Brookes try and attack, but Mossey was keeping his cool as Byrne held station in sixth place.
On the fifth lap Byrne went for a move on Haslam at Surtees, but ran out wide and dropped back three places, giving himself more work to do. At the front Brookes had hit the lead with a move, but Mossey was instantly fighting back and regained the position into Paddock Hill Bend.
A big crash for Shaun Winfield caused the first BMW Safety Car deployment of the season, but the Anvil Hire TAG Yamaha rider was able to walk away from the incident.
When the race resumed Hickman instantly went for a move as did Linfoot and by the end of the next lap it was Linfoot leading the way from Mossey, Hickman, Leon Haslam and Brookes with Christian Iddon also in close contention.
Hickman waited two more laps before he got his opportunity to snatch the lead; moving ahead at Surtees to push Linfoot back into second place.
Linfoot was coming under pressure from Mossey as he dived down the inside at Paddock Hill Bend on the twelfth lap but the Honda Racing rider fought back and repaid the move into Druids to regain the position.
Hickman was still leading the pack for the Smiths Racing BMW team with Linfoot, Mossey, Haslam and Iddon hot on their heels as Brookes dropped back and was fighting off James Ellison and Byrne.
Linfoot regained the lead on lap 16 with a decisive move at Paddock Hill Bend, but the defending champion was on the move and he had worked his way up the order to take the lead at Surtees with two laps remaining. The red flag was then bought out when light rain began to fall, but it was enough for Byrne to claim the win and with it move ahead in the overall standings.
Linfoot celebrated his first podium of the season for Honda Racing with Haslam returning to the podium for the first time since Oulton Park as he held off Hickman and Brookes.
MCE Insurance British Superbike Championship, Brands Hatch, Race one result:
Shane Byrne (Be Wiser Ducati)
Dan Linfoot (Honda Racing) +0.365s
Leon Haslam (JG Speedfit Kawasaki) +0.737s
Peter Hickman (Smiths Racing BMW) +0.795s
Josh Brookes (Anvil Hire TAG Yamaha) +1.535s
James Ellison (McAMS Yamaha) +1.717s
Jason O'Halloran (Honda Racing) +2.102s
Christian Iddon (Tyco BMW) +3.631s
John Hopkins (Moto Rapido Ducati) +3.708s
Bradley Ray (Buildbase Suzuki) +3.792s
MCE Insurance British Superbike Championship standings after Brands Hatch race one:
Shane Byrne (Be Wiser Ducati) 165
Luke Mossey (JG Speedfit Kawasaki) 151
Leon Haslam (JG Speedfit Kawasaki) 148
Josh Brookes (Anvil Hire TAG Yamaha) 129
Jason O'Halloran (Honda Racing) 124
Peter Hickman (Smiths Racing BMW) 106
