I found the solution to my question. AccessToken can be obtained by this->myObject->token() and the Header can be set using

m_networkRequest.setRawHeader("Authorization", "Bearer " + this->myObject->token().toUtf8());

So my code snippet becomes

// private // QOAuth2AuthorizationCodeFlow * myObject connect(this->myObject, &QOAuth2AuthorizationCodeFlow::granted, [=](){ qDebug() << __FUNCTION__ << __LINE__ << "Access Granted!"; QJsonObject obj; obj.insert("param1", "someval"); QJsonDocument doc(obj); QString strJson(doc.toJson(QJsonDocument::Compact)); QNetworkRequest m_networkRequest; m_networkRequest.setUrl(QUrl("API_URL")); m_networkRequest.setHeader(QNetworkRequest::ContentTypeHeader,"application/json"); m_networkRequest.setRawHeader("Authorization", "Bearer " + this->myObject->token().toUtf8()); auto m_networkReply = m_networkAccessManager->post(m_networkRequest, strJson.toUtf8()); connect(m_networkReply, &QNetworkReply::finished, [=](){ qDebug() << "REQUEST FINISHED. Error? " << (m_networkReply->error() != QNetworkReply::NoError); qDebug() << m_networkReply->readAll(); }); });