This was the first council meeting to be held face to face since Thursday, March 19, 2020, according to full Covid secure guidelines.
Coun Brookes lives in Swineshead and has served with the authority for 12 years.
His vice chairman will be Coun Alison Austin.
He has been impressed by the resilience and resourcefulness of Lincolnshire residents in the face of the Covid-19 pandemic over the last 13 months.
He said: "There's no doubt that the last year has been incredibly difficult for many residents and businesses.
"I've been impressed at how communities have pulled together and supported each other, and also proud that the county council continued to deliver key services, and support vulnerable people during these very challenging times.
"The work of the county's key workers, carers, community groups and individuals has been nothing short of amazing in these uncertain times.
"The hard work that has gone into ensuring the vaccination programme continues to be a success is truly tremendous and I am grateful for all they have done for us.
"Over the next year I'm looking forward to supporting the county as we follow the road map out of lockdown. While we need to be cautious and follow guidelines, I'm hopeful that there is much to look forward to now, as we ease back to normality.
"And I'm looking forward to celebrating all things Lincolnshire on October 1, which is Lincolnshire Day."