Coun Mark Jones will replace Coun Lewis Dagnall, who quit at the weekend, as Cabinet member for environment, streetscene and climate change.
He said he was keen to see more consultation with the public and work cross party with opposition councillors.
Coun Jones said: “I am excited about the prospect of doing this role. Coun Dagnall was already engaging with the public and I hope to continue that by reaching out to people and having more consultations.
“We often forget that we are not as clever as we think we are. I don’t know everything but collectively we know a lot so we need the input from the public to help us find solutions.
“We are setting up the Citizens Assembly and we need to do a lot more cross party working. I have been on scrutiny boards and have often worked with opposition councillors and I genuinely hope for more cross party working.
“It’s selfish and disrespectful to say one person has all the answers and tell people what they must do.”
Coun Jones, aged 48, was elected as a Burngreave councillor three years ago and said environmental issues range from the world stage to our doorsteps.
He added: “The climate emergency is very important and something that far too many global leaders have ignored for far too long. They have had their heads in the sand and have not taken this seriously.
“There are massive worldwide environmental issues but also smaller more local ones on our doorsteps. I have spent many hours in Page Hall looking at fixing the environment there.
“There’s litter and fly tipping and also problems with the houses and sewers. There’s a crumbling infrastructure which is not acceptable.
“We do need to tackle global warming but we also need to look at the smaller things. President Trump blankly denies humanity has an effect but if I see litter, that has been dropped by humans. The environment is all encompassing.”
Coun Jones was previously cabinet advisor for transport and development to Coun Bob Johnson and said the two portfolios were closely tied.
“I mostly walk or cycle but you need to make it easier for people to move around and public transport is critical,” he added.
“You can’t penalise car drivers until the public transport system is better.
“We can’t talk about climate change if we can’t tackle how we move around. I can’t preach about recycling or leaving your car at home if it’s not viable.
“My only regret in taking on this role of Cabinet member is leaving Coun Johnson as I worked closely with him.
“We’ll never go back to the days of 2p bus fares but we put a lot of money into the bus companies and there needs to be a balance between them making a profit and having affordable fares. We would also like to see cross ticketing between Stagecoach and First.
“I do sometimes get frustrated at how it can be difficult to turn things around but a quick fix will almost certainly never be a good fix.”
While he said he was keen to engage with people, he said social media wasn’t always the best platform.
“I don’t think it’s a great means of communication. Common decency can often disappear out of the window,” he added.
“I will talk to anybody with constructive opinions, councillors should not get special privileges but nor should we have to be in fear. As cabinet advisor, I was behind the scenes but as Cabinet member it will be more up close and personal and that will take some getting used to.”
Coun Dagnall was one of six councillors who resigned their Cabinet positions at the weekend. His wife Coun Olivia Blake quit suddenly as Deputy Leader. Her replacement will be chosen at a meeting of the Labour Group on Monday.
They were joined by Councillors Fran Johnson, Sophie Wilson, Moya O’Rourke and Adam Hurst, who resigned as Cabinet advisors and assistants.
All six left their posts to support It’s Our City, which has seen a 26,000 name petition handed into the Town Hall. Campaigners want a committee system rather than a ruling Cabinet and look set to force a referendum on it.