After telling his fellow Welsh Assembly members he had bowel cancer, Steffan Lewis said he had been inundated with messages of support from politicians from all parties.
The father-of-one was diagnosed with stage four cancer in December.
The Plaid Cymru AM said while the assembly was sometimes criticised for being too cosy it was great politicians could "just be there for each other".
"I've never once felt alone," said Mr Lewis.
He made the comments as AMs and MPs from across the political divide joined his family on an 11-mile charity walk in his name on Saturday.
The 34-year-old said it was "uplifting" politicians had rallied around him since his diagnosis.
"As soon as my diagnosis became public I was receiving messages and cards from people of all political colours and none," he told BBC Radio Wales' Good Morning Wales programme.
"We get a lot of criticism in Wales for having a cosy politics.
"But I think it's good that we have a political atmosphere where somebody is facing a life changing situation like I am - we can put political divisions to one side and we can just be there for each other.
"I think that's something to be celebrated.
"I'm so grateful and thankful to all my friends, and colleagues and family who have made sure that along this journey I've never once felt alone."
Mr Lewis will join the last mile of the walk from Cwmcarn to Blackwood, which was organised by his younger sister, Nia, as a birthday present to her brother.
Former Welsh Conservative leader Andrew RT Davies, presiding officer Elin Jones and Labour local government minister Alun Davies are among those expected to take part in the walk, to raise money for Velindre Cancer Centre, Cardiff, where Mr Lewis has been treated.
Another walk will take place in Llandudno, Conwy county. So far, more than £9,000 has been raised.
"I'm having excellent care from Velindre. They've been with me almost from the very beginning of this journey," said Mr Lewis, who is currently on a break in his chemotherapy and is on a trial of a drug that aims to control his cancer.
"They do such a great job. They really are the jewel in the crown of the Welsh NHS.
"The phenomenal amount of money we're raising, I think, is going to make a big difference in terms of what Velindre can do for cancer patients and their families."